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  • Problem separating C++ code in header, inline functions and code.

    - by YuppieNetworking
    Hello all, I have the simplest code that I want to separate in three files: Header file: class and struct declarations. No implementations at all. Inline functions file: implementation of inline methods in header. Code file: normal C++ code for more complicated implementations. When I was about to implement an operator[] method, I couldn't manage to compile it. Here is a minimal example that shows the same problem: Header (myclass.h): #ifndef _MYCLASS_H_ #define _MYCLASS_H_ class MyClass { public: MyClass(const int n); virtual ~MyClass(); double& operator[](const int i); double operator[](const int i) const; void someBigMethod(); private: double* arr; }; #endif /* _MYCLASS_H_ */ Inline functions (myclass-inl.h): #include "myclass.h" inline double& MyClass::operator[](const int i) { return arr[i]; } inline double MyClass::operator[](const int i) const { return arr[i]; } Code (myclass.cpp): #include "myclass.h" #include "myclass-inl.h" #include <iostream> inline MyClass::MyClass(const int n) { arr = new double[n]; } inline MyClass::~MyClass() { delete[] arr; } void MyClass::someBigMethod() { std::cout << "Hello big method that is not inlined" << std::endl; } And finally, a main to test it all: #include "myclass.h" #include <iostream> using namespace std; int main(int argc, char *argv[]) { MyClass m(123); double x = m[1]; m[1] = 1234; cout << "m[1]=" << m[1] << endl; x = x + 1; return 0; } void nothing() { cout << "hello world" << endl; } When I compile it, it says: main.cpp:(.text+0x1b): undefined reference to 'MyClass::MyClass(int)' main.cpp:(.text+0x2f): undefined reference to 'MyClass::operator[](int)' main.cpp:(.text+0x49): undefined reference to 'MyClass::operator[](int)' main.cpp:(.text+0x65): undefined reference to 'MyClass::operator[](int)' However, when I move the main method to the MyClass.cpp file, it works. Could you guys help me spot the problem? Thank you.

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  • Why wont my while loop wont take new input (c++)

    - by Van
    I've written a program to get a string input from a user and parse it into tokens and move a robot according to the input. My problem is trying to issue more than one command. The code looks like: void Navigator::manualDrive() { const int bufSize = 42; char uinput[bufSize]; char delim[] = " "; char *token; while(true) { Navigator::parseInstruction(uinput); } } /* parseInstruction(char *c) -- parses cstring instructions received * and moves robot accordingly */ void Navigator::parseInstruction(char * c) { const int bufSize = 42; char uinput[bufSize]; char delim[] = " "; char *token; cout << "Enter your directions below: \n"; cin.ignore(); cin.getline (uinput, bufSize); token=strtok(uinput, delim); if(strcmp("forward", token) == 0) { int inches; token = strtok(NULL, delim); inches = atoi (token); Navigator::travel(inches); } if(strcmp("back",token) == 0) { int inches; token = strtok(NULL, delim); inches = atoi (token); double value = fabs(0.0735 * fabs(inches) - 0.0550); myRobot.backward(1/*speed*/, value/*time*/); } if(strcmp("turn",token) == 0) { int degrees; token = strtok(NULL, delim); if(strcmp("left",token) == 0) { token = strtok(uinput, delim); degrees = atoi (token); double value = fabs(0.0041 * degrees - 0.0523); myRobot.turnLeft(1/*speed*/, value/*time*/); } } if(strcmp("turn",token) == 0) { int degrees; token = strtok(NULL, delim); if(strcmp("right",token) == 0) { token = strtok(uinput, delim); degrees = atoi (token); double value = fabs(0.0041 * degrees - 0.0523); myRobot.turnRight(1/*speed*/, value/*time*/); } } if(strcmp("stop",token) == 0) { myRobot.motors(0,0); } } In the function manualDrive I have a while loop calling the function parseInstruction infinitely. The program outputs "Enter your directions below: " When I give the program instructions it executes them, and then it outputs "enter your directions below: " again and when I input my directions again it does not execute them and outputs "Enter your directions below: " instead. I'm sure this is a very simple fix I'm just very new to c++. So if you could please help me out and tell me why the program only takes the first set of directions. thanks

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  • weird performance in C++ (VC 2010)

    - by raicuandi
    Hello, I have this loop written in C++, that compiled with MSVC2010 takes a long time to run. (300ms) for (int i=0; i<h; i++) { for (int j=0; j<w; j++) { if (buf[i*w+j] > 0) { const int sy = max(0, i - hr); const int ey = min(h, i + hr + 1); const int sx = max(0, j - hr); const int ex = min(w, j + hr + 1); float val = 0; for (int k=sy; k < ey; k++) { for (int m=sx; m < ex; m++) { val += original[k*w + m] * ds[k - i + hr][m - j + hr]; } } heat_map[i*w + j] = val; } } } It seemed a bit strange to me, so I did some tests then changed a few bits to inline assembly: (specifically, the code that sums "val") for (int i=0; i<h; i++) { for (int j=0; j<w; j++) { if (buf[i*w+j] > 0) { const int sy = max(0, i - hr); const int ey = min(h, i + hr + 1); const int sx = max(0, j - hr); const int ex = min(w, j + hr + 1); __asm { fldz } for (int k=sy; k < ey; k++) { for (int m=sx; m < ex; m++) { float val = original[k*w + m] * ds[k - i + hr][m - j + hr]; __asm { fld val fadd } } } float val1; __asm { fstp val1 } heat_map[i*w + j] = val1; } } } Now it runs in half the time, 150ms. It does exactly the same thing, but why is it twice as quick? In both cases it was run in Release mode with optimizations on. Am I doing anything wrong in my original C++ code?

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  • infix operation to postfix using stacks

    - by Chris De La O
    We are writing a program that needs to convert an infix operation (4 5/3) to postfix (4 5 3 / ) using stacks. however my convert to postfix does not work as it doesnt not output the postFix array that is supposed to store the conversion from infix notation to postfix notation. here is the code for the convertToPostix fuction. //converts infix expression to postfix expression void ArithmeticExpression::convertToPostfix(char *const inFix, char *const postFix) { //create a stack2 object named cow Stack2<char> cow; cout<<postFix; char thing = '('; //push a left parenthesis onto the stack cow.push(thing); //append a right parenthesis to the end of inFix array strcat(inFix, ")"); int i = 0;//declare an int that will control posFix position //if the stack is not empty if (!cow.isEmpty()) { //loop to run until the last character in inFix array for (int x = 0; inFix[x]!= '\0'; x++ ) { //if the inFix element is a digit if (isdigit(inFix[x])) { postFix[i]=inFix[x];//it is assigned to the next element in postFix array i++;//move on to next element in postFix } //if the inFix element is a left parenthesis else if (inFix[x]=='(') { cow.push(inFix[x]);//push it unto the stack } //if the inFix element is an operator else if (isOperator(inFix[x])) { char oper2 = inFix[x];//char variable holds inFix operator if (isOperator(cow.stackTop()))//if the top node in the stack is an operator { while (isOperator(cow.stackTop()))//and while the top node in the stack is an operator { char oper1 = cow.stackTop();//char variable holds node operator if(precedence( oper1, oper2))//if the node operator has higher presedence than node operator { postFix[i] = cow.pop();//we pop such operator and insert it in postFix array's next element cow.push(inFix[x]);//and push inFix operator unto the stack i++;//move to the next element in posFix } } } //if the top node is not an operator //we push the current inFix operator unto the top of the stack else cow.push(inFix[x]); } //if the inFix element is a right parenthesis else if (inFix[x]==')') { //we pop everything in the stack and insert it in postFix //until we arrive at a left paranthesis while (cow.stackTop()!='(') { postFix[i] = cow.pop(); i++; } //we then pop and discard left parenthesis cow.pop(); } } postFix[i]='\0'; //print !!postFix array!! (not stack) print();//code for this is just cout<<postFix; }

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  • C socket programming: select() is returning 0 despite messages sent from server

    - by Fantastic Fourier
    Hey all, I'm using select() to recv() messages from server, using TCP/IP. When I send() messages from the server, it returns a reasonable number of bytes, saying it's sent successful. And it does get to the client successfully when I use while loop to just recv(). Everything is fine and dandy. while(1) recv() // obviously pseudocode However, when I try to use select(), select() returns 0 from timeout (which is set to 1 second) and for the life of me I cannot figure out why it doesn't see the messages sent from the server. I should also mention that when the server disconnects, select() doesn't see that either, where as if I were to use recv(), it would return 0 to indicate that the connection using the socket has been closed. Any inputs or thoughts are deeply appreciated. #include <arpa/inet.h> #include <errno.h> #include <fcntl.h> #include <netdb.h> #include <netinet/in.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include <sys/select.h> #include <sys/socket.h> #include <sys/time.h> #include <sys/types.h> #include <time.h> #include <unistd.h> #define SERVER_PORT 10000 #define MAX_CONNECTION 20 #define MAX_MSG 50 struct client { char c_name[MAX_MSG]; char g_name[MAX_MSG]; int csock; int host; // 0 = not host of a multicast group struct sockaddr_in client_address; struct client * next_host; struct client * next_client; }; struct fd_info { char c_name[MAX_MSG]; int socks_inuse[MAX_CONNECTION]; int sock_fd, max_fd; int exit; struct client * c_sys; struct sockaddr_in c_address[MAX_CONNECTION]; struct sockaddr_in server_address; struct sockaddr_in client_address; fd_set read_set; }; struct message { char c_name[MAX_MSG]; char g_name[MAX_MSG]; char _command[3][MAX_MSG]; char _payload[MAX_MSG]; struct sockaddr_in client_address; struct client peer; }; int main(int argc, char * argv[]) { char * host; char * temp; int i, sockfd; int msg_len, rv, ready; int connection, management, socketread; int sockfds[MAX_CONNECTION]; // for three threads that handle new connections, user inputs and select() for sockets pthread_t connection_handler, manager, socket_reader; struct sockaddr_in server_address, client_address; struct hostent * hserver, cserver; struct timeval timeout; struct message msg; struct fd_info info; info.exit = 0; // exit information: if exit = 1, threads quit info.c_sys = NULL; // looking up from the host database if (argc == 3) { host = argv[1]; // server address strncpy(info.c_name, argv[2], strlen(argv[2])); // client name } else { printf("plz read the manual, kthxbai\n"); exit(1); } printf("host is %s and hp is %p\n", host, hserver); hserver = gethostbyname(host); if (hserver) { printf("host found: %s\n", hserver->h_name ); } else { printf("host not found\n"); exit(1); } // setting up address and port structure information on serverside bzero((char * ) &server_address, sizeof(server_address)); // copy zeroes into string server_address.sin_family = AF_INET; memcpy(&server_address.sin_addr, hserver->h_addr, hserver->h_length); server_address.sin_port = htons(SERVER_PORT); bzero((char * ) &client_address, sizeof(client_address)); // copy zeroes into string client_address.sin_family = AF_INET; client_address.sin_addr.s_addr = htonl(INADDR_ANY); client_address.sin_port = htons(SERVER_PORT); // opening up socket sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd < 0) exit(1); else { printf("socket is opened: %i \n", sockfd); info.sock_fd = sockfd; } // sets up time out option for the bound socket timeout.tv_sec = 1; // seconds timeout.tv_usec = 0; // micro seconds ( 0.5 seconds) setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timeval)); // binding socket to a port rv = bind(sockfd, (struct sockaddr *) &client_address, sizeof(client_address)); if (rv < 0) { printf("MAIN: ERROR bind() %i: %s\n", errno, strerror(errno)); exit(1); } else printf("socket is bound\n"); printf("MAIN: %li \n", client_address.sin_addr.s_addr); // connecting rv = connect(sockfd, (struct sockaddr *) &server_address, sizeof(server_address)); info.server_address = server_address; info.client_address = client_address; info.sock_fd = sockfd; info.max_fd = sockfd; printf("rv = %i\n", rv); if (rv < 0) { printf("MAIN: ERROR connect() %i: %s\n", errno, strerror(errno)); exit(1); } else printf("connected\n"); fd_set readset; FD_ZERO(&readset); FD_ZERO(&info.read_set); FD_SET(info.sock_fd, &info.read_set); while(1) { readset = info.read_set; printf("MAIN: %i \n", readset); ready = select((info.max_fd)+1, &readset, NULL, NULL, &timeout); if(ready == -1) { sleep(2); printf("TEST: MAIN: ready = -1. %s \n", strerror(errno)); } else if (ready == 0) { sleep(2); printf("TEST: MAIN: ready = 0. %s \n", strerror(errno)); } else if (ready > 0) { printf("TEST: MAIN: ready = %i. %s at socket %i \n", ready, strerror(errno), i); for(i = 0; i < ((info.max_fd)+1); i++) { if(FD_ISSET(i, &readset)) { rv = recv(sockfd, &msg, 500, 0); if(rv < 0) continue; else if(rv > 0) printf("MAIN: TEST: %s %s \n", msg._command[0], msg._payload); else if (rv == 0) { sleep(3); printf("MAIN: TEST: SOCKET CLOSEDDDDDD \n"); } FD_CLR(i, &readset); } } } info.read_set = readset; } // close connection close(sockfd); printf("socket closed. BYE! \n"); return(0); }

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  • Basic data alignment question

    - by Broken Logic
    I've been playing around to see how my computer works under the hood. What I'm interested in is seeing is what happens on the stack inside a function. To do this I've written the following toy program: #include <stdio.h> void __cdecl Test1(char a, unsigned long long b, char c) { char c1; unsigned long long b1; char a1; c1 = 'b'; b1 = 4; a1 = 'r'; printf("%d %d - %d - %d %d Total: %d\n", (long)&b1 - (long)&a1, (long)&c1 - (long)&b1, (long)&a - (long)&c1, (long)&b - (long)&a, (long)&c - (long)&b, (long)&c - (long)&a1 ); }; struct TestStruct { char a; unsigned long long b; char c; }; void __cdecl Test2(char a, unsigned long long b, char c) { TestStruct locals; locals.a = 'b'; locals.b = 4; locals.c = 'r'; printf("%d %d - %d - %d %d Total: %d\n", (long)&locals.b - (long)&locals.a, (long)&locals.c - (long)&locals.b, (long)&a - (long)&locals.c, (long)&b - (long)&a, (long)&c - (long)&b, (long)&c - (long)&locals.a ); }; int main() { Test1('f', 0, 'o'); Test2('f', 0, 'o'); return 0; } And this spits out the following: 9 19 - 13 - 4 8 Total: 53 8 8 - 24 - 4 8 Total: 52 The function args are well behaved but as the calling convention is specified, I'd expect this. But the local variables are a bit wonky. My question is, why wouldn't these be the same? The second call seems to produce a more compact and better aligned stack. Looking at the ASM is unenlightening (at least to me), as the variable addresses are still aliased there. So I guess this is really a question about the assembler itself allocates the stack to local variables. I realise that any specific answer is likely to be platform specific. I'm more interested in a general explanation unless this quirk really is platform specific. For the record though, I'm compiling with VS2010 on a 64bit Intel machine.

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  • Using nested classes for constants?

    - by antirysm
    What's wrong with using nested classes to group constants? Like so: public static class Constants { public static class CategoryA { public const string ValueX = "CatA_X"; public const string ValueY = "CatA_Y"; } public static class CategoryB { public const string ValueX = "CatB_X"; public const string ValueY = "CatB_Y"; } } Used like so: Console.WriteLine(Constants.CategoryA.ValueY); Console.WriteLine(Constants.CategoryB.ValueX); You could also make the "Constants"-class partial...

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  • Types questions in ANSI C

    - by shaharg
    Hi, I having few questions about typed in ANSI C: 1. what's the difference between "\x" in the beginning of a char to 0x in the beginning of char (or in any other case for this matter). AFAIK, they both means that this is hexadecimal.. so what's the difference. when casting char to (unsigned), not (unsigned char) - what does it mean? why (unsigned)'\xFF' != 0xFF? Thanks!

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  • C Array of string

    - by Meko
    HI. This is maybe simple question but I want to create two dimensional array and add it string like in java string str = "text" ; string [][] array = new [][] string ; array[i][j] = str ; But in C there is no string .I tried like this but here strcpy() gives error.It returns to assembly code. I am trying to read line by line from text and split line by space and add them to structure.But first I think that I must add each line and row in array and then making iteration and adding to structures fields. static const char filename[] = "student.txt"; FILE *file = fopen ( filename, "r" ); char line [ 128 ]; /* or other suitable maximum line size */ char delims [ ]=" "; char *result =NULL; char list[15]; char arra[128][128]; int i=0; int j=0; struct { char gruppa[10]; char familiya[20]; int uchaste; struct { int firsth; int second; int third; int fourht; int fifth; } exam; }student; for(i=0; i<128; i++) for(j=0; j<128; j++) arra[i][j] = '\0'; for(i=0; i<15; i++) list[i] = '\0'; if ( file != NULL ) { while ( fgets ( line, sizeof line, file ) != NULL ) { result = strtok(line,delims); while (result !=NULL) { strcpy(list,("%s",result)); strcpy(arra[i][j],list); // Here it gives errror j++; result = strtok(NULL,delims); } j=0; i++; } fclose ( file ); } else { perror ( filename ); } getchar(); return 0; }

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  • replacing a path with sed

    - by compie
    How can I use sed to replace this line char * path_list_[1] = { "/some/random/path" }; with this line char * path_list_[2] = { "lib/foo", "lib/bar" }; in a file named source.c Notes: * The path is really random. * Your solution should only change this line in source.c * I'm only interested in a sed oneliner. You can use this Python regex as a starting point: text = re.sub('static const char \* path_list_\[1\] = \{ "[^"]*" \};', 'static const char * path_list_[2] = { "lib/sun", "lib/matlab" };', text)

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  • How to fix a warning message associated with strlen() used in Yacc?

    - by user547894
    Hello! Please i need your help. Basically, I am facing this warning message upon compiling with gcc, and am not able to deduce the error: Here are the details: The warning message i am receiving is literrally as follows: y.tab.c: In function ‘yyparse’: y.tab.c:1317 warning: incompatible implicit declaration of built-in function ‘strlen’ My Lex File looks like: %{ #include <stdio.h> #include <stdlib.h> #include <ctype.h> #include "y.tab.h" void yyerror(const char*); char *ptrStr; %} %START nameState %% "Name:" { BEGIN nameState; } <nameState>.+ { ptrStr = (char *)calloc(strlen(yytext)+1, sizeof(char)); strcpy(ptrStr, yytext); yylval.sValue = ptrStr; return sText; } %% int main(int argc, char *argv[]) { if ( argc < 3 ) { printf("Two args are needed: input and output"); } else { yyin = fopen(argv[1], "r"); yyout = fopen(argv[2], "w"); yyparse(); fclose(yyin); fclose(yyout); } return 0; } My Yacc file is as follows: %{ #include <stdio.h> #include <stdlib.h> #include <ctype.h> #include "y.tab.h" void yyerror(const char*); int yywrap(); extern FILE *yyout; %} %union { int iValue; char* sValue; }; %token <sValue> sText %token nameToken %% StartName: /* for empty */ | sName ; sName: sText { fprintf(yyout, "The Name is: %s", $1); fprintf(yyout, "The Length of the Name is: %d", strlen($1)); } ; %% void yyerror(const char *str) { fprintf(stderr,"error: %s\n",str); } int yywrap() { return 1; } *I was wondering how to remove this warning message. Please any suggestions are highly appreciated! Thanks in advance.

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  • Xerces conflicts string.h

    - by Velthune
    Compiling my program I have this error: /usr/include/xercesc/util/Compilers/GCCDefs.hpp:133:60: error: declaration of ‘int strcasecmp(const char*, const char*)’ has a different exception specifier /usr/include/string.h:536:12: error: from previous declaration ‘int strcasecmp(const char*, const char*) throw ()’ make: *** [src/test/VFTImageMaterial.o] Error 1 Any idea about this conflict with string.h?

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  • What's the purpose of the unnamed namespace?

    - by bbazso
    In a .cpp file, if I decare a constant as follows: namespace { const int UDP_PORT_MIN = 1024; const int UDP_PORT_MAX = 65535; } vs. just: const int UDP_PORT_MIN = 1024; const int UDP_PORT_MAX = 65535; What's the difference between these two? I often see constant definitions declared in an unnamed namespace, so I was wondering what's the purpose of the unnamed namespace in this context?

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  • Split a binary file into chunks c++

    - by L4nce0
    I've been bashing my head against trying to first divide up a file into chunks, for the purpose of sending over sockets. I can read / write a file easily without splitting it into chunks. The code below runs, works, kinda. It will write a textfile and has a garbage character. Which if this was just for txt, no problem. Jpegs aren't working with said garbage. Been at it for a few days, so I've done my research, and it's time to get some help. I do want to stick strictly to binary readers, as this need to handle any file. I've seen a lot of slick examples out there. (none of them worked for me with jpgs) Mostly something along the lines of while(file)... I subscribe to the, if you know the size, use a for-loop, not a while-loop camp. Thank you for the help!! vector<char*> readFile(const char* fn){ vector<char*> v; ifstream::pos_type size; char * memblock; ifstream file; file.open(fn,ios::in|ios::binary|ios::ate); if (file.is_open()) { size = fileS(fn); file.seekg (0, ios::beg); int bs = size/3; // arbitrary. Actual program will use the socket send size int ws = 0; int i = 0; for(i = 0; i < size; i+=bs){ if(i+bs > size) ws = size%bs; else ws = bs; memblock = new char [ws]; file.read (memblock, ws); v.push_back(memblock); } } else{ exit(-4); } return v; } int main(int argc, char **argv) { vector<char*> v = readFile("foo.txt"); ofstream myFile ("bar.txt", ios::out | ios::binary); for(vector<char*>::iterator it = v.begin(); it!=v.end(); ++it ){ myFile.write(*it,strlen(*it)); } }

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  • Need advice about pointers and time elapsed program. How to fix invalid operands and cannot convert errors?

    - by user1781382
    I am trying to write a program that tells the difference between the two times the user inputs. I am not sure how to go about this. I get the errors : Line 27|error: invalid operands of types 'int' and 'const MyTime*' to binary 'operator-'| Line |39|error: cannot convert 'MyTime' to 'const MyTime*' for argument '1' to 'int DetermineElapsedTime(const MyTime*, const MyTime*)'| I also need a lot of help in this problem. I don't have a good curriculum, and my class textbook is like cliffnotes for programming. This will be my last class at this university. The C++ teztbook I use(my own not for class) is Sam's C++ One hour a day. #include <iostream> #include<cstdlib> #include<cstring> using namespace std; struct MyTime { int hours, minutes, seconds; }; int DetermineElapsedTime(const MyTime *t1, const MyTime *t2); long t1, t2; int DetermineElapsedTime(const MyTime *t1, const MyTime *t2) { return((int)t2-t1); } int main(void) { char delim1, delim2; MyTime tm, tm2; cout << "Input two formats for the time. Separate each with a space. Ex: hr:min:sec\n"; cin >> tm.hours >> delim1 >> tm.minutes >> delim2 >> tm.seconds; cin >> tm2.hours >> delim1 >> tm2.minutes >> delim2 >> tm2.seconds; DetermineElapsedTime(tm, tm2); return 0; } I have to fix the errors first. Anyone have any ideas??

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  • Adding Functions to an Implementation of Vector

    - by Meursault
    I have this implementation of vector that I've been working on for a few days using examples from a textbook: #include <iostream> #include <string> #include <cassert> #include <algorithm> #include <cstring> // Vector.h using namespace std; template <class T> class Vector { public: typedef T * iterator; Vector(); Vector(unsigned int size); Vector(unsigned int size, const T & initial); Vector(const Vector<T> & v); // copy constructor ~Vector(); unsigned int capacity() const; // return capacity of vector (in elements) unsigned int size() const; // return the number of elements in the vector bool empty() const; iterator begin(); // return an iterator pointing to the first element iterator end(); // return an iterator pointing to one past the last element T & front(); // return a reference to the first element T & back(); // return a reference to the last element void push_back(const T & value); // add a new element void pop_back(); // remove the last element void reserve(unsigned int capacity); // adjust capacity void resize(unsigned int size); // adjust size void erase(unsigned int size); // deletes an element from the vector T & operator[](unsigned int index); // return reference to numbered element Vector<T> & operator=(const Vector<T> &); private: unsigned int my_size; unsigned int my_capacity; T * buffer; }; template<class T>// Vector<T>::Vector() { my_capacity = 0; my_size = 0; buffer = 0; } template<class T> Vector<T>::Vector(const Vector<T> & v) { my_size = v.my_size; my_capacity = v.my_capacity; buffer = new T[my_size]; for (int i = 0; i < my_size; i++) buffer[i] = v.buffer[i]; } template<class T>// Vector<T>::Vector(unsigned int size) { my_capacity = size; my_size = size; buffer = new T[size]; } template<class T>// Vector<T>::Vector(unsigned int size, const T & initial) { my_size = size; //added = size my_capacity = size; buffer = new T [size]; for (int i = 0; i < size; i++) buffer[i] = initial; } template<class T>// Vector<T> & Vector<T>::operator = (const Vector<T> & v) { delete[ ] buffer; my_size = v.my_size; my_capacity = v.my_capacity; buffer = new T [my_size]; for (int i = 0; i < my_size; i++) buffer[i] = v.buffer[i]; return *this; } template<class T>// typename Vector<T>::iterator Vector<T>::begin() { return buffer; } template<class T>// typename Vector<T>::iterator Vector<T>::end() { return buffer + size(); } template<class T>// T& Vector<T>::Vector<T>::front() { return buffer[0]; } template<class T>// T& Vector<T>::Vector<T>::back() { return buffer[size - 1]; } template<class T> void Vector<T>::push_back(const T & v) { if (my_size >= my_capacity) reserve(my_capacity +5); buffer [my_size++] = v; } template<class T>// void Vector<T>::pop_back() { my_size--; } template<class T>// void Vector<T>::reserve(unsigned int capacity) { if(buffer == 0) { my_size = 0; my_capacity = 0; } if (capacity <= my_capacity) return; T * new_buffer = new T [capacity]; assert(new_buffer); copy (buffer, buffer + my_size, new_buffer); my_capacity = capacity; delete[] buffer; buffer = new_buffer; } template<class T>// unsigned int Vector<T>::size()const { return my_size; } template<class T>// void Vector<T>::resize(unsigned int size) { reserve(size); my_size = size; } template<class T>// T& Vector<T>::operator[](unsigned int index) { return buffer[index]; } template<class T>// unsigned int Vector<T>::capacity()const { return my_capacity; } template<class T>// Vector<T>::~Vector() { delete[]buffer; } template<class T> void Vector<T>::erase(unsigned int size) { } int main() { Vector<int> v; v.reserve(2); assert(v.capacity() == 2); Vector<string> v1(2); assert(v1.capacity() == 2); assert(v1.size() == 2); assert(v1[0] == ""); assert(v1[1] == ""); v1[0] = "hi"; assert(v1[0] == "hi"); Vector<int> v2(2, 7); assert(v2[1] == 7); Vector<int> v10(v2); assert(v10[1] == 7); Vector<string> v3(2, "hello"); assert(v3.size() == 2); assert(v3.capacity() == 2); assert(v3[0] == "hello"); assert(v3[1] == "hello"); v3.resize(1); assert(v3.size() == 1); assert(v3[0] == "hello"); Vector<string> v4 = v3; assert(v4.size() == 1); assert(v4[0] == v3[0]); v3[0] = "test"; assert(v4[0] != v3[0]); assert(v4[0] == "hello"); v3.pop_back(); assert(v3.size() == 0); Vector<int> v5(7, 9); Vector<int>::iterator it = v5.begin(); while (it != v5.end()) { assert(*it == 9); ++it; } Vector<int> v6; v6.push_back(100); assert(v6.size() == 1); assert(v6[0] == 100); v6.push_back(101); assert(v6.size() == 2); assert(v6[0] == 100); v6.push_back(101); cout << "SUCCESS\n"; } So far it works pretty well, but I want to add a couple of functions to it that I can't find examples for, a SWAP function that would look at two elements of the vector and switch their values and and an ERASE function that would delete a specific value or range of values in the vector. How should I begin implementing the two extra functions?

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  • SQL Server &ndash; Undelete a Table and Restore a Single Table from Backup

    - by Mladen Prajdic
    This post is part of the monthly community event called T-SQL Tuesday started by Adam Machanic (blog|twitter) and hosted by someone else each month. This month the host is Sankar Reddy (blog|twitter) and the topic is Misconceptions in SQL Server. You can follow posts for this theme on Twitter by looking at #TSQL2sDay hashtag. Let me start by saying: This code is a crazy hack that is to never be used unless you really, really have to. Really! And I don’t think there’s a time when you would really have to use it for real. Because it’s a hack there are number of things that can go wrong so play with it knowing that. I’ve managed to totally corrupt one database. :) Oh… and for those saying: yeah yeah.. you have a single table in a file group and you’re restoring that, I say “nay nay” to you. As we all know SQL Server can’t do single table restores from backup. This is kind of a obvious thing due to different relational integrity (RI) concerns. Since we have to maintain that we have to restore all tables represented in a RI graph. For this exercise i say BAH! to those concerns. Note that this method “works” only for simple tables that don’t have LOB and off rows data. The code can be expanded to include those but I’ve tried to leave things “simple”. Note that for this to work our table needs to be relatively static data-wise. This doesn’t work for OLTP table. Products are a perfect example of static data. They don’t change much between backups, pretty much everything depends on them and their table is one of those tables that are relatively easy to accidentally delete everything from. This only works if the database is in Full or Bulk-Logged recovery mode for tables where the contents have been deleted or truncated but NOT when a table was dropped. Everything we’ll talk about has to be done before the data pages are reused for other purposes. After deletion or truncation the pages are marked as reusable so you have to act fast. The best thing probably is to put the database into single user mode ASAP while you’re performing this procedure and return it to multi user after you’re done. How do we do it? We will be using an undocumented but known DBCC commands: DBCC PAGE, an undocumented function sys.fn_dblog and a little known DATABASE RESTORE PAGE option. All tests will be on a copy of Production.Product table in AdventureWorks database called Production.Product1 because the original table has FK constraints that prevent us from truncating it for testing. -- create a duplicate table. This doesn't preserve indexes!SELECT *INTO AdventureWorks.Production.Product1FROM AdventureWorks.Production.Product   After we run this code take a full back to perform further testing.   First let’s see what the difference between DELETE and TRUNCATE is when it comes to logging. With DELETE every row deletion is logged in the transaction log. With TRUNCATE only whole data page deallocations are logged in the transaction log. Getting deleted data pages is simple. All we have to look for is row delete entry in the sys.fn_dblog output. But getting data pages that were truncated from the transaction log presents a bit of an interesting problem. I will not go into depths of IAM(Index Allocation Map) and PFS (Page Free Space) pages but suffice to say that every IAM page has intervals that tell us which data pages are allocated for a table and which aren’t. If we deep dive into the sys.fn_dblog output we can see that once you truncate a table all the pages in all the intervals are deallocated and this is shown in the PFS page transaction log entry as deallocation of pages. For every 8 pages in the same extent there is one PFS page row in the transaction log. This row holds information about all 8 pages in CSV format which means we can get to this data with some parsing. A great help for parsing this stuff is Peter Debetta’s handy function dbo.HexStrToVarBin that converts hexadecimal string into a varbinary value that can be easily converted to integer tus giving us a readable page number. The shortened (columns removed) sys.fn_dblog output for a PFS page with CSV data for 1 extent (8 data pages) looks like this: -- [Page ID] is displayed in hex format. -- To convert it to readable int we'll use dbo.HexStrToVarBin function found at -- http://sqlblog.com/blogs/peter_debetta/archive/2007/03/09/t-sql-convert-hex-string-to-varbinary.aspx -- This function must be installed in the master databaseSELECT Context, AllocUnitName, [Page ID], DescriptionFROM sys.fn_dblog(NULL, NULL)WHERE [Current LSN] = '00000031:00000a46:007d' The pages at the end marked with 0x00—> are pages that are allocated in the extent but are not part of a table. We can inspect the raw content of each data page with a DBCC PAGE command: -- we need this trace flag to redirect output to the query window.DBCC TRACEON (3604); -- WITH TABLERESULTS gives us data in table format instead of message format-- we use format option 3 because it's the easiest to read and manipulate further onDBCC PAGE (AdventureWorks, 1, 613, 3) WITH TABLERESULTS   Since the DBACC PAGE output can be quite extensive I won’t put it here. You can see an example of it in the link at the beginning of this section. Getting deleted data back When we run a delete statement every row to be deleted is marked as a ghost record. A background process periodically cleans up those rows. A huge misconception is that the data is actually removed. It’s not. Only the pointers to the rows are removed while the data itself is still on the data page. We just can’t access it with normal means. To get those pointers back we need to restore every deleted page using the RESTORE PAGE option mentioned above. This restore must be done from a full backup, followed by any differential and log backups that you may have. This is necessary to bring the pages up to the same point in time as the rest of the data.  However the restore doesn’t magically connect the restored page back to the original table. It simply replaces the current page with the one from the backup. After the restore we use the DBCC PAGE to read data directly from all data pages and insert that data into a temporary table. To finish the RESTORE PAGE  procedure we finally have to take a tail log backup (simple backup of the transaction log) and restore it back. We can now insert data from the temporary table to our original table by hand. Getting truncated data back When we run a truncate the truncated data pages aren’t touched at all. Even the pointers to rows stay unchanged. Because of this getting data back from truncated table is simple. we just have to find out which pages belonged to our table and use DBCC PAGE to read data off of them. No restore is necessary. Turns out that the problems we had with finding the data pages is alleviated by not having to do a RESTORE PAGE procedure. Stop stalling… show me The Code! This is the code for getting back deleted and truncated data back. It’s commented in all the right places so don’t be afraid to take a closer look. Make sure you have a full backup before trying this out. Also I suggest that the last step of backing and restoring the tail log is performed by hand. USE masterGOIF OBJECT_ID('dbo.HexStrToVarBin') IS NULL RAISERROR ('No dbo.HexStrToVarBin installed. Go to http://sqlblog.com/blogs/peter_debetta/archive/2007/03/09/t-sql-convert-hex-string-to-varbinary.aspx and install it in master database' , 18, 1) SET NOCOUNT ONBEGIN TRY DECLARE @dbName VARCHAR(1000), @schemaName VARCHAR(1000), @tableName VARCHAR(1000), @fullBackupName VARCHAR(1000), @undeletedTableName VARCHAR(1000), @sql VARCHAR(MAX), @tableWasTruncated bit; /* THE FIRST LINE ARE OUR INPUT PARAMETERS In this case we're trying to recover Production.Product1 table in AdventureWorks database. My full backup of AdventureWorks database is at e:\AW.bak */ SELECT @dbName = 'AdventureWorks', @schemaName = 'Production', @tableName = 'Product1', @fullBackupName = 'e:\AW.bak', @undeletedTableName = '##' + @tableName + '_Undeleted', @tableWasTruncated = 0, -- copy the structure from original table to a temp table that we'll fill with restored data @sql = 'IF OBJECT_ID(''tempdb..' + @undeletedTableName + ''') IS NOT NULL DROP TABLE ' + @undeletedTableName + ' SELECT *' + ' INTO ' + @undeletedTableName + ' FROM [' + @dbName + '].[' + @schemaName + '].[' + @tableName + ']' + ' WHERE 1 = 0' EXEC (@sql) IF OBJECT_ID('tempdb..#PagesToRestore') IS NOT NULL DROP TABLE #PagesToRestore /* FIND DATA PAGES WE NEED TO RESTORE*/ CREATE TABLE #PagesToRestore ([ID] INT IDENTITY(1,1), [FileID] INT, [PageID] INT, [SQLtoExec] VARCHAR(1000)) -- DBCC PACE statement to run later RAISERROR ('Looking for deleted pages...', 10, 1) -- use T-LOG direct read to get deleted data pages INSERT INTO #PagesToRestore([FileID], [PageID], [SQLtoExec]) EXEC('USE [' + @dbName + '];SELECT FileID, PageID, ''DBCC TRACEON (3604); DBCC PAGE ([' + @dbName + '], '' + FileID + '', '' + PageID + '', 3) WITH TABLERESULTS'' as SQLToExecFROM (SELECT DISTINCT LEFT([Page ID], 4) AS FileID, CONVERT(VARCHAR(100), ' + 'CONVERT(INT, master.dbo.HexStrToVarBin(SUBSTRING([Page ID], 6, 20)))) AS PageIDFROM sys.fn_dblog(NULL, NULL)WHERE AllocUnitName LIKE ''%' + @schemaName + '.' + @tableName + '%'' ' + 'AND Context IN (''LCX_MARK_AS_GHOST'', ''LCX_HEAP'') AND Operation in (''LOP_DELETE_ROWS''))t');SELECT *FROM #PagesToRestore -- if upper EXEC returns 0 rows it means the table was truncated so find truncated pages IF (SELECT COUNT(*) FROM #PagesToRestore) = 0 BEGIN RAISERROR ('No deleted pages found. Looking for truncated pages...', 10, 1) -- use T-LOG read to get truncated data pages INSERT INTO #PagesToRestore([FileID], [PageID], [SQLtoExec]) -- dark magic happens here -- because truncation simply deallocates pages we have to find out which pages were deallocated. -- we can find this out by looking at the PFS page row's Description column. -- for every deallocated extent the Description has a CSV of 8 pages in that extent. -- then it's just a matter of parsing it. -- we also remove the pages in the extent that weren't allocated to the table itself -- marked with '0x00-->00' EXEC ('USE [' + @dbName + '];DECLARE @truncatedPages TABLE(DeallocatedPages VARCHAR(8000), IsMultipleDeallocs BIT);INSERT INTO @truncatedPagesSELECT REPLACE(REPLACE(Description, ''Deallocated '', ''Y''), ''0x00-->00 '', ''N'') + '';'' AS DeallocatedPages, CHARINDEX('';'', Description) AS IsMultipleDeallocsFROM (SELECT DISTINCT LEFT([Page ID], 4) AS FileID, CONVERT(VARCHAR(100), CONVERT(INT, master.dbo.HexStrToVarBin(SUBSTRING([Page ID], 6, 20)))) AS PageID, DescriptionFROM sys.fn_dblog(NULL, NULL)WHERE Context IN (''LCX_PFS'') AND Description LIKE ''Deallocated%'' AND AllocUnitName LIKE ''%' + @schemaName + '.' + @tableName + '%'') t;SELECT FileID, PageID , ''DBCC TRACEON (3604); DBCC PAGE ([' + @dbName + '], '' + FileID + '', '' + PageID + '', 3) WITH TABLERESULTS'' as SQLToExecFROM (SELECT LEFT(PageAndFile, 1) as WasPageAllocatedToTable , SUBSTRING(PageAndFile, 2, CHARINDEX('':'', PageAndFile) - 2 ) as FileID , CONVERT(VARCHAR(100), CONVERT(INT, master.dbo.HexStrToVarBin(SUBSTRING(PageAndFile, CHARINDEX('':'', PageAndFile) + 1, LEN(PageAndFile))))) as PageIDFROM ( SELECT SUBSTRING(DeallocatedPages, delimPosStart, delimPosEnd - delimPosStart) as PageAndFile, IsMultipleDeallocs FROM ( SELECT *, CHARINDEX('';'', DeallocatedPages)*(N-1) + 1 AS delimPosStart, CHARINDEX('';'', DeallocatedPages)*N AS delimPosEnd FROM @truncatedPages t1 CROSS APPLY (SELECT TOP (case when t1.IsMultipleDeallocs = 1 then 8 else 1 end) ROW_NUMBER() OVER(ORDER BY number) as N FROM master..spt_values) t2 )t)t)tWHERE WasPageAllocatedToTable = ''Y''') SELECT @tableWasTruncated = 1 END DECLARE @lastID INT, @pagesCount INT SELECT @lastID = 1, @pagesCount = COUNT(*) FROM #PagesToRestore SELECT @sql = 'Number of pages to restore: ' + CONVERT(VARCHAR(10), @pagesCount) IF @pagesCount = 0 RAISERROR ('No data pages to restore.', 18, 1) ELSE RAISERROR (@sql, 10, 1) -- If the table was truncated we'll read the data directly from data pages without restoring from backup IF @tableWasTruncated = 0 BEGIN -- RESTORE DATA PAGES FROM FULL BACKUP IN BATCHES OF 200 WHILE @lastID <= @pagesCount BEGIN -- create CSV string of pages to restore SELECT @sql = STUFF((SELECT ',' + CONVERT(VARCHAR(100), FileID) + ':' + CONVERT(VARCHAR(100), PageID) FROM #PagesToRestore WHERE ID BETWEEN @lastID AND @lastID + 200 ORDER BY ID FOR XML PATH('')), 1, 1, '') SELECT @sql = 'RESTORE DATABASE [' + @dbName + '] PAGE = ''' + @sql + ''' FROM DISK = ''' + @fullBackupName + '''' RAISERROR ('Starting RESTORE command:' , 10, 1) WITH NOWAIT; RAISERROR (@sql , 10, 1) WITH NOWAIT; EXEC(@sql); RAISERROR ('Restore DONE' , 10, 1) WITH NOWAIT; SELECT @lastID = @lastID + 200 END /* If you have any differential or transaction log backups you should restore them here to bring the previously restored data pages up to date */ END DECLARE @dbccSinglePage TABLE ( [ParentObject] NVARCHAR(500), [Object] NVARCHAR(500), [Field] NVARCHAR(500), [VALUE] NVARCHAR(MAX) ) DECLARE @cols NVARCHAR(MAX), @paramDefinition NVARCHAR(500), @SQLtoExec VARCHAR(1000), @FileID VARCHAR(100), @PageID VARCHAR(100), @i INT = 1 -- Get deleted table columns from information_schema view -- Need sp_executeSQL because database name can't be passed in as variable SELECT @cols = 'select @cols = STUFF((SELECT '', ['' + COLUMN_NAME + '']''FROM ' + @dbName + '.INFORMATION_SCHEMA.COLUMNSWHERE TABLE_NAME = ''' + @tableName + ''' AND TABLE_SCHEMA = ''' + @schemaName + '''ORDER BY ORDINAL_POSITIONFOR XML PATH('''')), 1, 2, '''')', @paramDefinition = N'@cols nvarchar(max) OUTPUT' EXECUTE sp_executesql @cols, @paramDefinition, @cols = @cols OUTPUT -- Loop through all the restored data pages, -- read data from them and insert them into temp table -- which you can then insert into the orignial deleted table DECLARE dbccPageCursor CURSOR GLOBAL FORWARD_ONLY FOR SELECT [FileID], [PageID], [SQLtoExec] FROM #PagesToRestore ORDER BY [FileID], [PageID] OPEN dbccPageCursor; FETCH NEXT FROM dbccPageCursor INTO @FileID, @PageID, @SQLtoExec; WHILE @@FETCH_STATUS = 0 BEGIN RAISERROR ('---------------------------------------------', 10, 1) WITH NOWAIT; SELECT @sql = 'Loop iteration: ' + CONVERT(VARCHAR(10), @i); RAISERROR (@sql, 10, 1) WITH NOWAIT; SELECT @sql = 'Running: ' + @SQLtoExec RAISERROR (@sql, 10, 1) WITH NOWAIT; -- if something goes wrong with DBCC execution or data gathering, skip it but print error BEGIN TRY INSERT INTO @dbccSinglePage EXEC (@SQLtoExec) -- make the data insert magic happen here IF (SELECT CONVERT(BIGINT, [VALUE]) FROM @dbccSinglePage WHERE [Field] LIKE '%Metadata: ObjectId%') = OBJECT_ID('['+@dbName+'].['+@schemaName +'].['+@tableName+']') BEGIN DELETE @dbccSinglePage WHERE NOT ([ParentObject] LIKE 'Slot % Offset %' AND [Object] LIKE 'Slot % Column %') SELECT @sql = 'USE tempdb; ' + 'IF (OBJECTPROPERTY(object_id(''' + @undeletedTableName + '''), ''TableHasIdentity'') = 1) ' + 'SET IDENTITY_INSERT ' + @undeletedTableName + ' ON; ' + 'INSERT INTO ' + @undeletedTableName + '(' + @cols + ') ' + STUFF((SELECT ' UNION ALL SELECT ' + STUFF((SELECT ', ' + CASE WHEN VALUE = '[NULL]' THEN 'NULL' ELSE '''' + [VALUE] + '''' END FROM ( -- the unicorn help here to correctly set ordinal numbers of columns in a data page -- it's turning STRING order into INT order (1,10,11,2,21 into 1,2,..10,11...21) SELECT [ParentObject], [Object], Field, VALUE, RIGHT('00000' + O1, 6) AS ParentObjectOrder, RIGHT('00000' + REVERSE(LEFT(O2, CHARINDEX(' ', O2)-1)), 6) AS ObjectOrder FROM ( SELECT [ParentObject], [Object], Field, VALUE, REPLACE(LEFT([ParentObject], CHARINDEX('Offset', [ParentObject])-1), 'Slot ', '') AS O1, REVERSE(LEFT([Object], CHARINDEX('Offset ', [Object])-2)) AS O2 FROM @dbccSinglePage WHERE t.ParentObject = ParentObject )t)t ORDER BY ParentObjectOrder, ObjectOrder FOR XML PATH('')), 1, 2, '') FROM @dbccSinglePage t GROUP BY ParentObject FOR XML PATH('') ), 1, 11, '') + ';' RAISERROR (@sql, 10, 1) WITH NOWAIT; EXEC (@sql) END END TRY BEGIN CATCH SELECT @sql = 'ERROR!!!' + CHAR(10) + CHAR(13) + 'ErrorNumber: ' + ERROR_NUMBER() + '; ErrorMessage' + ERROR_MESSAGE() + CHAR(10) + CHAR(13) + 'FileID: ' + @FileID + '; PageID: ' + @PageID RAISERROR (@sql, 10, 1) WITH NOWAIT; END CATCH DELETE @dbccSinglePage SELECT @sql = 'Pages left to process: ' + CONVERT(VARCHAR(10), @pagesCount - @i) + CHAR(10) + CHAR(13) + CHAR(10) + CHAR(13) + CHAR(10) + CHAR(13), @i = @i+1 RAISERROR (@sql, 10, 1) WITH NOWAIT; FETCH NEXT FROM dbccPageCursor INTO @FileID, @PageID, @SQLtoExec; END CLOSE dbccPageCursor; DEALLOCATE dbccPageCursor; EXEC ('SELECT ''' + @undeletedTableName + ''' as TableName; SELECT * FROM ' + @undeletedTableName)END TRYBEGIN CATCH SELECT ERROR_NUMBER() AS ErrorNumber, ERROR_MESSAGE() AS ErrorMessage IF CURSOR_STATUS ('global', 'dbccPageCursor') >= 0 BEGIN CLOSE dbccPageCursor; DEALLOCATE dbccPageCursor; ENDEND CATCH-- if the table was deleted we need to finish the restore page sequenceIF @tableWasTruncated = 0BEGIN -- take a log tail backup and then restore it to complete page restore process DECLARE @currentDate VARCHAR(30) SELECT @currentDate = CONVERT(VARCHAR(30), GETDATE(), 112) RAISERROR ('Starting Log Tail backup to c:\Temp ...', 10, 1) WITH NOWAIT; PRINT ('BACKUP LOG [' + @dbName + '] TO DISK = ''c:\Temp\' + @dbName + '_TailLogBackup_' + @currentDate + '.trn''') EXEC ('BACKUP LOG [' + @dbName + '] TO DISK = ''c:\Temp\' + @dbName + '_TailLogBackup_' + @currentDate + '.trn''') RAISERROR ('Log Tail backup done.', 10, 1) WITH NOWAIT; RAISERROR ('Starting Log Tail restore from c:\Temp ...', 10, 1) WITH NOWAIT; PRINT ('RESTORE LOG [' + @dbName + '] FROM DISK = ''c:\Temp\' + @dbName + '_TailLogBackup_' + @currentDate + '.trn''') EXEC ('RESTORE LOG [' + @dbName + '] FROM DISK = ''c:\Temp\' + @dbName + '_TailLogBackup_' + @currentDate + '.trn''') RAISERROR ('Log Tail restore done.', 10, 1) WITH NOWAIT;END-- The last step is manual. Insert data from our temporary table to the original deleted table The misconception here is that you can do a single table restore properly in SQL Server. You can't. But with little experimentation you can get pretty close to it. One way to possible remove a dependency on a backup to retrieve deleted pages is to quickly run a similar script to the upper one that gets data directly from data pages while the rows are still marked as ghost records. It could be done if we could beat the ghost record cleanup task.

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  • Build problems when adding `__str__` method to Boost Python C++ class

    - by Rickard
    I have started to play around with boost python a bit and ran into a problem. I tried to expose a C++ class to python which posed no problems. But I can't seem to manage to implement the __str__ functionality for the class without getting build errors I don't understand. I'm using boost 1_42 prebuild by boostpro. I build the library using cmake and the vs2010 compiler. I have a very simple setup. The header-file (tutorial.h) looks like the following: #include <iostream> namespace TestBoostPython{ class TestClass { private: double m_x; public: TestClass(double x); double Get_x() const; void Set_x(double x); }; std::ostream &operator<<(std::ostream &ostr, const TestClass &ts); }; and the corresponding cpp-file looks like: #include <boost/python.hpp> #include "tutorial.h" using namespace TestBoostPython; TestClass::TestClass(double x) { m_x = x; } double TestClass::Get_x() const { return m_x; } void TestClass::Set_x(double x) { m_x = x; } std::ostream &operator<<(std::ostream &ostr, TestClass &ts) { ostr << ts.Get_x() << "\n"; return ostr; } BOOST_PYTHON_MODULE(testme) { using namespace boost::python; class_<TestClass>("TestClass", init<double>()) .add_property("x", &TestClass::Get_x, &TestClass::Set_x) .def(str(self)) ; } The CMakeLists.txt looks like the following: CMAKE_MINIMUM_REQUIRED(VERSION 2.8) project (testme) FIND_PACKAGE( Boost REQUIRED ) FIND_PACKAGE( Boost COMPONENTS python REQUIRED ) FIND_PACKAGE( PythonLibs REQUIRED ) set(Boost_USE_STATIC_LIBS OFF) set(Boost_USE_MULTITHREAD ON) INCLUDE_DIRECTORIES(${Boost_INCLUDE_DIRS}) INCLUDE_DIRECTORIES ( ${PYTHON_INCLUDE_PATH} ) add_library(testme SHARED tutorial.cpp) target_link_libraries(testme ${Boost_PYTHON_LIBRARY}) target_link_libraries(testme ${PYTHON_LIBRARY} The build error I get is the following: Compiling... tutorial.cpp C:\Program Files (x86)\boost\boost_1_42\boost/python/def_visitor.hpp(31) : error C2780: 'void boost::python::api::object_operators::visit(ClassT &,const char *,const boost::python::detail::def_helper &) const' : expects 3 arguments - 1 provided with [ U=boost::python::api::object ] C:\Program Files (x86)\boost\boost_1_42\boost/python/object_core.hpp(203) : see declaration of 'boost::python::api::object_operators::visit' with [ U=boost::python::api::object ] C:\Program Files (x86)\boost\boost_1_42\boost/python/def_visitor.hpp(67) : see reference to function template instantiation 'void boost::python::def_visitor_access::visit,classT>(const V &,classT &)' being compiled with [ DerivedVisitor=boost::python::api::object, classT=boost::python::class_, V=boost::python::def_visitor ] C:\Program Files (x86)\boost\boost_1_42\boost/python/class.hpp(225) : see reference to function template instantiation 'void boost::python::def_visitor::visit>(classT &) const' being compiled with [ DerivedVisitor=boost::python::api::object, W=TestBoostPython::TestClass, classT=boost::python::class_ ] .\tutorial.cpp(29) : see reference to function template instantiation 'boost::python::class_ &boost::python::class_::def(const boost::python::def_visitor &)' being compiled with [ W=TestBoostPython::TestClass, U=boost::python::api::object, DerivedVisitor=boost::python::api::object ] Does anyone have any idea on what went wrrong? If I remove the .def(str(self)) part from the wrapper code, everything compiles fine and the class is usable from python. I'd be very greatful for assistance. Thank you, Rickard

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  • My VARCHAR(MAX) field is capping itself at 4000; what gives?

    - by eidylon
    Hello all... I have a table in one of my databases which is a queue of emails. Emails to certain addresses get accumulated into one email, which is done by a sproc. In the sproc, I have a table variable which I use to build the accumulated bodies of the emails, and then loop through to send each email. In my table var I have my body column defined as VARCHAR(MAX), seeing as there could be any number of emails currently accumulated for a given email address. It seems though that even though my column is defined as VARCHAR(MAX) it is behaving as if it were VARCHAR(4000) and is truncating the data going into it, although it does NOT throw any exceptions, it just silently stops concatenating any more data after 4000 characters. The MERGE statement is where it is building the accumulated email body into @EMAILS.BODY, which is the field that is truncating itself at 4000 characters. Below is the code of my sproc... ALTER PROCEDURE [system].[SendAccumulatedEmails] AS BEGIN SET NOCOUNT ON; DECLARE @SENTS BIGINT = 0; DECLARE @ROWS TABLE ( ROWID ROWID, DATED DATETIME, ADDRESS NAME, SUBJECT VARCHAR(1000), BODY VARCHAR(MAX) ) INSERT INTO @ROWS SELECT ROWID, DATED, ADDRESS, SUBJECT, BODY FROM system.EMAILQUEUE WHERE ACCUMULATE = 1 AND SENT IS NULL ORDER BY ADDRESS, DATED DECLARE @EMAILS TABLE ( ADDRESS NAME, ALLIDS VARCHAR(1000), BODY VARCHAR(MAX) ) DECLARE @PRVRID ROWID = NULL, @CURRID ROWID = NULL SELECT @CURRID = MIN(ROWID) FROM @ROWS WHILE @CURRID IS NOT NULL BEGIN MERGE @EMAILS AS DST USING (SELECT * FROM @ROWS WHERE ROWID = @CURRID) AS SRC ON SRC.ADDRESS = DST.ADDRESS WHEN MATCHED THEN UPDATE SET DST.ALLIDS = DST.ALLIDS + ', ' + CONVERT(VARCHAR,ROWID), DST.BODY = DST.BODY + '<i>'+CONVERT(VARCHAR,SRC.DATED,101)+' ' +CONVERT(VARCHAR,SRC.DATED,8) +':</i> <b>'+SRC.SUBJECT+'</b>'+CHAR(13)+SRC.BODY +' (Message ID '+CONVERT(VARCHAR,SRC.ROWID)+')' +CHAR(13)+CHAR(13) WHEN NOT MATCHED BY TARGET THEN INSERT (ADDRESS, ALLIDS, BODY) VALUES ( SRC.ADDRESS, CONVERT(VARCHAR,ROWID), '<i>'+CONVERT(VARCHAR,SRC.DATED,101)+' ' +CONVERT(VARCHAR,SRC.DATED,8)+':</i> <b>' +SRC.SUBJECT+'</b>'+CHAR(13)+SRC.BODY +' (Message ID '+CONVERT(VARCHAR,SRC.ROWID)+')' +CHAR(13)+CHAR(13)); SELECT @PRVRID = @CURRID, @CURRID = NULL SELECT @CURRID = MIN(ROWID) FROM @ROWS WHERE ROWID > @PRVRID END DECLARE @MAILFROM VARCHAR(100) = system.getOption('MAILFROM'), DECLARE @SMTPHST VARCHAR(100) = system.getOption('SMTPSERVER'), DECLARE @SMTPUSR VARCHAR(100) = system.getOption('SMTPUSER'), DECLARE @SMTPPWD VARCHAR(100) = system.getOption('SMTPPASS') DECLARE @ADDRESS NAME, @BODY VARCHAR(MAX), @ADDL VARCHAR(MAX) DECLARE @SUBJECT VARCHAR(1000) = 'Accumulated Emails from LIJSL' DECLARE @PRVID NAME = NULL, @CURID NAME = NULL SELECT @CURID = MIN(ADDRESS) FROM @EMAILS WHILE @CURID IS NOT NULL BEGIN SELECT @ADDRESS = ADDRESS, @BODY = BODY FROM @EMAILS WHERE ADDRESS = @CURID SELECT @BODY = @BODY + 'This is an automated message sent from an unmonitored mailbox.'+CHAR(13)+'Do not reply to this message; your message will not be read.' SELECT @BODY = '<style type="text/css"> * {font-family: Tahoma, Arial, Verdana;} p {margin-top: 10px; padding-top: 10px; border-top: single 1px dimgray;} p:first-child {margin-top: 10px; padding-top: 0px; border-top: none 0px transparent;} </style>' + @BODY exec system.LogIt @SUBJECT, @BODY BEGIN TRY exec system.SendMail @SMTPHST, @SMTPUSR, @SMTPPWD, @MAILFROM, @ADDRESS, NULL, NULL, @SUBJECT, @BODY, 1 END TRY BEGIN CATCH DECLARE @EMSG NVARCHAR(2048) = 'system.EMAILQUEUE.AI:'+ERROR_MESSAGE() SELECT @ADDL = 'TO:'+@ADDRESS+CHAR(13)+'SUBJECT:'+@SUBJECT+CHAR(13)+'BODY:'+@BODY exec system.LogIt @EMSG,@ADDL END CATCH SELECT @PRVID = @CURID, @CURID = NULL SELECT @CURID = MIN(ADDRESS) FROM @EMAILS WHERE ADDRESS > @PRVID END UPDATE system.EMAILQUEUE SET SENT = getdate() FROM system.EMAILQUEUE E, @ROWS R WHERE E.ROWID = R.ROWID END

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  • Help with simple linux shell implementation

    - by nunos
    I am implementing a simple version of a linux shell in c. I have succesfully written the parser, but I am having some trouble forking out the child process. However, I think the problem is due to arrays, pointers and such, because just started C with this project and am not still very knowledgable with them. I am getting a segmentation fault and don't know where from. Any help is greatly appreciated. #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <sys/wait.h> #include <sys/types.h> #define MAX_COMMAND_LENGTH 250 #define MAX_ARG_LENGTH 250 typedef enum {false, true} bool; typedef struct { char **arg; char *infile; char *outfile; int background; } Command_Info; int parse_cmd(char *cmd_line, Command_Info *cmd_info) { char *arg; char *args[MAX_ARG_LENGTH]; int i = 0; arg = strtok(cmd_line, " "); while (arg != NULL) { args[i] = arg; arg = strtok(NULL, " "); i++; } int num_elems = i; if (num_elems == 0) return -1; cmd_info->infile = NULL; cmd_info->outfile = NULL; cmd_info->background = 0; int iarg = 0; for (i = 0; i < num_elems-1; i++) { if (!strcmp(args[i], "<")) { if (args[i+1] != NULL) cmd_info->infile = args[++i]; else return -1; } else if (!strcmp(args[i], ">")) { if (args[i+1] != NULL) cmd_info->outfile = args[++i]; else return -1; } else cmd_info->arg[iarg++] = args[i]; } if (!strcmp(args[i], "&")) cmd_info->background = true; else cmd_info->arg[iarg++] = args[i]; cmd_info->arg[iarg] = NULL; return 0; } void print_cmd(Command_Info *cmd_info) { int i; for (i = 0; cmd_info->arg[i] != NULL; i++) printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("infile=\"%s\"\n", cmd_info->infile); printf("outfile=\"%s\"\n", cmd_info->outfile); printf("background=\"%d\"\n", cmd_info->background); } void get_cmd(char* str) { fgets(str, MAX_COMMAND_LENGTH, stdin); str[strlen(str)-1] = '\0'; //apaga o '\n' do fim } pid_t exec_simple(Command_Info *cmd_info) { pid_t pid = fork(); if (pid < 0) { perror("Fork Error"); return -1; } if (pid == 0) { execvp(cmd_info->arg[0], cmd_info->arg); perror(cmd_info->arg[0]); exit(1); } return pid; } int main(int argc, char* argv[]) { while (true) { char cmd_line[MAX_COMMAND_LENGTH]; Command_Info cmd_info; printf(">>> "); get_cmd(cmd_line); if ( (parse_cmd(cmd_line, &cmd_info) == -1) ) return -1; parse_cmd(cmd_line, &cmd_info); if (!strcmp(cmd_info.arg[0], "exit")) exit(0); pid_t pid = exec_simple(&cmd_info); waitpid(pid, NULL, 0); } return 0; } Thanks.

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  • Doxygen for C++ template class member specialization

    - by Ziv
    When I write class templates, and need to fully-specialize members of those classes, Doxygen doesn't recognize the specialization - it documents only the generic definition, or (if there are only specializations) the last definition. Here's a simple example: ===MyClass.hpp=== #ifndef MYCLASS_HPP #define MYCLASS_HPP template<class T> class MyClass{ public: static void foo(); static const int INT_CONST; static const T TTYPE_CONST; }; /* generic definitions */ template<class T> void MyClass<T>::foo(){ printf("Generic foo\n"); } template<class T> const int MyClass<T>::INT_CONST = 5; /* specialization declarations */ template<> void MyClass<double>::foo(); template<> const int MyClass<double>::INT_CONST; template<> const double MyClass<double>::TTYPE_CONST; template<> const char MyClass<char>::TTYPE_CONST; #endif === MyClass.cpp === #include "MyClass.hpp" /* specialization definitions */ template<> void MyClass<double>::foo(){ printf("Specialized double foo\n"); } template<> const int MyClass<double>::INT_CONST = 10; template<> const double MyClass<double>::TTYPE_CONST = 3.141; template<> const char MyClass<char>::TTYPE_CONST = 'a'; So in this case, foo() will be documented as printing "Generic foo," INT_CONST will be documented as set to 5, with no mention of the specializations, and TTYPE_CONST will be documented as set to 'a', with no mention of 3.141 and no indication that 'a' is a specialized case. I need to be able to document the specializations - either within the documentation for MyClass<T>, or on new pages for MyClass<double>, MyClass<char>. How do I do this? Can Doxygen even handle this? Am I possibly doing something wrong in the declarations/code structure that's keeping Doxygen from understanding what I want? I should note two related cases: A) For templated functions, specialization works fine, e.g.: /* functions that are global/in a namespace */ template<class T> void foo(){ printf("Generic foo\n"); } template<> void foo<double>(){ printf("Specialized double foo\n"); } This will document both foo() and foo(). B) If I redeclare the entire template, i.e. template<> class MyClass<double>{...};, then MyClass<double> will get its own documentation page, as a seperate class. But this means actually declaring an entirely new class - there is no relation between MyClass<T> and MyClass<double> if MyClass<double> itself is declared. So I'd have to redeclare the class and all its members, and repeat all the definitions of class members, specialized for MyClass<double>, all to make it appear as though they're using the same template. Very awkward, feels like a kludge solution. Suggestions? Thanks much :) --Ziv

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  • how to add a function to that program, and call that function from the command line in the function

    - by user336291
    a#include "smallsh.h" /*include file for example*/ /*program buffers and work pointers*/ static char inpbuf[MAXBUF], tokbuf[2*MAXBUF], *ptr = inpbuf, *tok = tokbuf; userin(p) /*print prompt and read a line*/ char *p; { int c, count; /*initialization for later routines*/ ptr = inpbuf; tok = tokbuf; /*display prompt*/ printf("%s ",p); for(count = 0;;) { if((c = getchar()) == EOF) return(EOF); if(count<MAXBUF) inpbuf[count++] = c; if(c == '\n' && count <MAXBUF) { inpbuf[count] = '\0'; return(count); } /*if line too long restart*/ if(c == '\n') { printf("smallsh:input line too long\n"); count = 0; printf("%s",p); } } } gettok(outptr) /*get token and place into tokbuf*/ char **outptr; { int type; *outptr = tok; /*strip white space*/ for(;*ptr == ' ' || *ptr == '\t'; ptr++) ; *tok++ = *ptr; switch(*ptr++) { case '\n': type = EOL; break; case '&': type = AMPERSAND; break; case ';': type = SEMICOLON; break; case '#': type = POUND; break; default: type = ARG; while(inarg(*ptr)) *tok++ = *ptr++; } *tok++ = '\0'; return(type); } static char special[]= {' ', '\t', '&', ':', '\n', '\0'}; inarg(c) /*are we in an ordinary argument*/ char c; { char *wrk; for(wrk = special;*wrk != '\0';wrk++) if(c == *wrk) return(0); return(1); } #include "smallsh.h" procline() /*process input line*/ { char *arg[MAXARG+1]; /*pointer array for runcommand*/ int toktype; /*type of token in command*/ int narg; /*number of arguments so far*/ int type; /*FOREGROUND or BACKGROUND*/ for(narg = 0;;) { /*loop FOREVER*/ /*take action according to token type*/ switch(toktype = gettok(&arg[narg])) { case ARG: if(narg<MAXARG) narg++; break; case EOL: case SEMICOLON: case AMPERSAND: case POUND: type = (toktype == AMPERSAND) ? BACKGROUND : FOREGROUND; if(narg!=0) { arg[narg] = NULL; runcommand(arg, type); } if((toktype == EOL)||(toktype=POUND)) return; narg = 0; break; } } } #include "smallsh.h" /*execute a command with optional wait*/ runcommand(cline,where) char **cline; int where; { int pid, exitstat, ret; if((pid = fork()) <0) { perror("smallsh"); return(-1); } if(pid == 0) { /*child*/ execvp(*cline, cline); perror(*cline); exit(127); } /*code for parent*/ /*if background process print pid and exit*/ if(where == BACKGROUND) { printf("[Process id %d]\n", pid); return(0); } /*wait until process pid exists*/ while( (ret=wait(&exitstat)) != pid && ret != -1) ; return(ret == -1 ? -1 : exitstat); } #include "smallsh.h" char *prompt = "Command>"; /*prompt*/ main() { while(userin(prompt) != EOF) procline(); }

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