Search Results

Search found 14000 results on 560 pages for 'include guards'.

Page 142/560 | < Previous Page | 138 139 140 141 142 143 144 145 146 147 148 149  | Next Page >

  • Correct Exceptions in C++

    - by Dr.Ackula
    I am just learning how to handle errors in my C++ code. I wrote this example that looks for a text file called some file, and if its not found will throw an exception. #include <iostream> #include <fstream> using namespace std; int main() { int array[90]; try { ifstream file; file.open("somefile.txt"); if(!file.good()) throw 56; } catch(int e) { cout<<"Error number "<<e<<endl; } return 0; } Now I have two questions. First I would like to know if I am using Exceptions correctly. Second, (assuming the first is true) what is the benefit to using them vs an If else statement?

    Read the article

  • where to put business logic in a library?

    - by fayer
    i'm going to create a library that consists of a lot of separate classes. i'm very familiar with mvc but have never created a pure library before. i wonder where i should put the business logic? the logic that is in the controller in a mvc. should it be in a class? or in a "bootstrap" file? and should one file include every class, or should only one class include its classes it uses? thanks!

    Read the article

  • Searching for range overlaps in Ruby hashes

    - by mbm
    Say you have the following Ruby hash, hash = {:a => [[1, 100..300], [2, 200..300]], :b => [[1, 100..300], [2, 301..400]] } and the following functions, def overlaps?(range, range2) range.include?(range2.begin) || range2.include?(range.begin) end def any_overlaps?(ranges) # This calls to_proc on the symbol object; it's syntactically equivalent to # ranges.sort_by {|r| r.begin} ranges.sort_by(&:begin).each_cons(2).any? do |r1, r2| overlaps?(r1, r2) end end and it's your desire to, for each key in hash, test whether any range overlaps with any other. In hash above, I would expect hash[:a] to make me mad and hash[:b] to not. How is this best implemented syntactically?

    Read the article

  • C++ Euler-Problem 14 Program Freezing

    - by Tim
    I'm working on Euler Problem 14: http://projecteuler.net/index.php?section=problems&id=14 I figured the best way would be to create a vector of numbers that kept track of how big the series was for that number... for example from 5 there are 6 steps to 1, so if ever reach the number 5 in a series, I know I have 6 steps to go and I have no need to calculate those steps. With this idea I coded up the following: #include <iostream> #include <vector> #include <iomanip> using namespace std; int main() { vector<int> sizes(1); sizes.push_back(1); sizes.push_back(2); int series, largest = 0, j; for (int i = 3; i <= 1000000; i++) { series = 0; j = i; while (j > (sizes.size()-1)) { if (j%2) { j=(3*j+1)/2; series+=2; } else { j=j/2; series++; } } series+=sizes[j]; sizes.push_back(series); if (series>largest) largest=series; cout << setw(7) << right << i << "::" << setw(5) << right << series << endl; } cout << largest << endl; return 0; } It seems to work relatively well for smaller numbers but this specific program stalls at the number 113382. Can anyone explain to me how I would go about figuring out why it freezes at this number? Is there some way I could modify my algorithim to be better? I realize that I am creating duplicates with the current way I'm doing it: for example, the series of 3 is 3,10,5,16,8,4,2,1. So I already figured out the sizes for 10,5,16,8,4,2,1 but I will duplicate those solutions later. Thanks for your help!

    Read the article

  • How do I get a array to just count how many numbers there are instead of counting the value of each number?

    - by Chad Loos
    //This is the output of the program *** start of 276 2D Arrays_03.cpp program *** Number Count Total 1 3 3 2 6 9 3 15 24 4 6 30 5 9 39 *** end of 276 2D Arrays_03.cpp program *** #include <iostream> #include <string> #include <iomanip> using namespace std; const int COLUMN_SIZE = 13; int main(void) { const int ROW_SIZE = 3; const int COUNT_SIZE = 5; void countValues(const int[][COLUMN_SIZE], const int, int[]); void display(const int [], const int); int numbers[ROW_SIZE][COLUMN_SIZE] = {{1, 3, 4, 5, 3, 2, 3, 5, 3, 4, 5, 3, 2}, {2, 1, 3, 4, 5, 3, 2, 3, 5, 3, 4, 5, 3}, {3, 4, 5, 3, 2, 1, 3, 4, 5, 3, 2, 3, 5}}; int counts[COUNT_SIZE] = {0}; string choice; cout << "*** start of 276 2D Arrays_03.cpp program ***" << endl; cout << endl; countValues(numbers, ROW_SIZE, counts); display(counts, COUNT_SIZE); cout << endl; cout << endl; cout << "*** end of 276 2D Arrays_03.cpp program ***" << endl << endl; cin.get(); return 0; } // end main() This is the function where I need to count each of the values. I know how to sum rows and cols, but I'm not quite sure of the code to just tally the values themselves. void countValues(const int numbers[][COLUMN_SIZE], const int ROW_SIZE, int counts[]) This is what I have so far. { for (int index = 0; index < ROW_SIZE; index++) counts[index]; {

    Read the article

  • Using sizeof with a dynamically allocated array

    - by robUK
    Hello, gcc 4.4.1 c89 I have the following code snippet: #include <stdlib.h> #include <stdio.h> char *buffer = malloc(10240); /* Check for memory error */ if(!buffer) { fprintf(stderr, "Memory error\n"); return 1; } printf("sizeof(buffer) [ %d ]\n", sizeof(buffer)); However, the sizeof(buffer) always prints 4. I know that a char* is only 4 bytes. However, I have allocated the memory for 10kb. So shouldn't the size be 10240? I am wondering am I thinking right here? Many thanks for any suggestions,

    Read the article

  • Unit testing a functions whose purposes is side effects

    - by David
    How would you unit test do_int_to_string_conversion? #include <string> #include <iostream> void do_int_to_string_conversion(int i, std::string& s) { switch(i) { case 1: s="1"; break; case 2: s="2"; break; default: s ="Nix"; } std::cout << s << "\n"; } int main(int argc, char** argv){ std::string little_s; do_int_to_string_conversion(1, little_s); do_int_to_string_conversion(2, little_s); do_int_to_string_conversion(3, little_s); }

    Read the article

  • What is wrong in this c++ code?

    - by narayanpatra
    Why this coder do not show error #include <iostream> int main() { using namespace std; unsigned short int myInt = 99; unsigned short int * pMark = 0; cout << myInt << endl; pMark = &myInt; *pMark = 11; cout << "*pMark:\t" << *pMark << "\nmyInt:\t" << myInt << endl; return 0; } But this one shows : #include<iostream> using namespace std; int addnumber(int *p, int *q){ cout << *p = 12 << endl; cout << *q = 14 << endl; } #include<iostream> using namespace std; int addnumber(int *p, int *q){ cout << *p = 12 << endl; cout << *q = 14 << endl; } int main() { int i , j; cout << "enter the value of first number"; cin >> i; cout << "enter the value of second number"; cin >> j; addnumber(&i, &j); cout << i << endl; cout << j << endl; } In both the code snippets, I am assigning *pointer=somevalue. In first code it do not show any error but it shows error in the line cout << *p = 12 << endl; cout << *q = 14 << endl; What mistake I am doing ?

    Read the article

  • Is it a header file or library? in a makefile

    - by gccinac
    I already know the differences between a header file and a library. However, when I'm writing my makefile, I have some difficulties on deciding if I should put something as a dependency of the file or just at the linking rule. For example: I have 2 simple files: main.c: #include <stdio.h> main(){ printf("this is the sine or 90"); sinus(90); } and func.c: #include <math.h> sinus(int num){ return sin(num); } and my makefile is: main: main.o func.o gcc main.o func.o -lm -o main func.o: func.c main.o: main.c Well, my question is why this makefile works and this one doesn't: main: main.o func.o gcc main.o func.o -lm -o main func.o: func.c math.h main.o: main.c

    Read the article

  • assigning a string to another string

    - by user1509676
    Why this code is not running? Why str1 is not assigned to str2 ?? I know i have an option of using strcpy but i wish to know the reason why this is not working?? #include<stdio.h> int main() { char str1[]="hello"; char str2[10]; str2=str1; printf("%s",str2); return 0; } Whereas if I use pointers than it works like here.. #include<stdio.h> int main() ( char *s="good morning"; char *q; q=s; while(*q!='\0') { printf("%c",*q); q++; } return 0; } This works. Now the string has been copied via pointers so why such difference??

    Read the article

  • simple c++ file opening issue

    - by Robert
    #include <iostream> #include <fstream> using namespace std; int main () { ofstream testfile; testfile.open ("test.txt"); testfile << "success!\n"; testfile.close(); return 0; } 1)called "g++ testfile.cpp" 2)created "test.txt" 3)called "chmod u+x a.out" 4)??? 5)file remains blank. I feel like an idiot for failing at something as trivial as this is supposed to be.

    Read the article

  • For text-align:right; in TD, why does "style" work and "class" not?

    - by Will Fastie
    If I include this in a table cell: <td style="text-align: right; font-style: italic; color: maroon;">... the contents of the cell are aligned as I expect. If I include the following CSS: .right-notice { text-align: right; font-style: italic; color: maroon; } and this cell: <td class=".right-notice">... the contents of the cell are not right aligned. Why is this? What don't I know? If I change the CSS to replace text-align with float, that works. Thanks.

    Read the article

  • How can I get cmake to find my boost installation

    - by BD at Rivenhill
    I have installed the most recent version of boost in /usr/local (with includes in /usr/local/boost and libraries in /usr/local/lib/boost) and I am now attempting to install Wt from source, but cmake (version 2.6) can't seem to find the boost installation. It tries to give helpful suggestions about setting BOOST_DIR and Boost_LIBRARYDIR, but I haven't been able to get it to work by tweaking these variables. The most recent error message that I get is that it can't find the libraries, but it seems to indicate that it is using "/usr/local/include" for the include path, which isn't correct (and I can't seem to fix it). Does anybody have a solution for this off the top of their head, or do I need to go mucking around inside cmake to figure it out?

    Read the article

  • xcode 4 creating a 2d grid (range and domain)

    - by user1706978
    I'm learning how to program c and i'm trying to make a program the finds the range (using an equation with x as the domain) of a 2d grid...ive already attempted it, but it's giving me all these errors on Xcode, any help?(As you can see, I'm quite stuck!) #include <stdio.h> #include <stdlib.h> float domain; float domain = 2.0; float domainsol(float x ) { domain = x; float func = 1.25 * x + 5.0; return func; } int main(int argc, const char * argv[]) { }

    Read the article

  • "...redeclared as different kind of symbol"?

    - by CodeNewb
    #include <stdio.h> #include <math.h> double integrateF(double low, double high) { double low = 0; double high = 20; double delta_x=0; double x, ans; double s = 1/2*exp((-x*x)/2); for(x=low;x<=high;x++) delta_x = x+delta_x; ans = delta_x*s; return ans; } It says that low and high are "redeclared as different type of symbol" and I don't know what that means. Basically, all I'm doing here (READ: trying) is integrating from low (which I set to 0) to high (20) to find the Riemann sum. The for loop looks kinda trippy too...I'm so lost.

    Read the article

  • C++ dynamic type construction and detection

    - by KneLL
    There was an interesting problem in C++, but it concerns more likely architecture. There are many (10, 20, 40, etc) classes that describe some characteristics (mix-in classes), for exmaple: struct Base { virtual ~Base() {} }; struct A : virtual public Base { int size; }; struct B : virtual public Base { float x, y; }; struct C : virtual public Base { bool some_bool_state; }; struct D : virtual public Base { string str; } // .... Primary module declares and exports a function (for simplicity just function declarations without classes): // .h file void operate(Base *pBase); // .cpp file void operate(Base *pBase) { // .... } Any other module can has a code like this: #include "mixins.h" #include "primary.h" class obj1_t : public A, public C, public D {}; class obj2_t : public B, public D {}; // ... void Pass() { obj1_t obj1; obj2_t obj2; operate(&obj1); operate(&obj2); } The question is how to know what the real type of given object in operate() without dynamic_cast and any type information in classes (constants, etc)? Function operate() is used with big array of objects in small time periods and dynamic_cast is too slow for it. And I don't want to include constants (enum obj_type { ... }) because this is not OOP-way. // module operate.cpp void some_operate(Base *pBase) { processA(pBase); processB(pBase); } void processA(A *pA) { } void processB(B *pB) { } I cannot directly pass a pBase to these functions. And it's impossible to have all possible combinations of classes, because I can add new classes just by including new .h files. As one of solutions that comed to mind, in editor application I can use a composite container: struct CompositeObject { vector<Base *pBase> parts; }; But editor does not need a time optimization and can use dynamic_cast for parts to determine the exact type. In operate() I cannot use this solution. So, is it possible to not use a dynamic_cast and type information to solve this problem? Or maybe I should use another architecture?

    Read the article

  • regex no character

    - by iamnotmad
    In this text: warning here there are several types of warnings in this string warning.gif at the end warning end of line warning I want to match every warning except warning.gif. I cannot seem to get it to include the last one that has no character (control or otherwise) after it. using warnings?[^\.] gets what I want except for the last warning (on the last line). I think because there is no character at all after. How can I get it to include that one?

    Read the article

  • PHP, since upgrading to 5.2.17 getting some warning ?

    - by Jules
    I can't reproduce this on my test server no idea why this is happening, other queries / functions work.. I'm getting this warning PHP Warning: mysql_connect() [<a href='function.mysql-connect'> function.mysql-connect</a>]: Can't connect to MySQL server on '--my isps server--' (10060) in D:\domains\mydomain.com\wwwroot\p hp\_stdfuncs.php on line 191 This function and others like it are having problems (but some are ok), this is my include file... function AddPageError($PageHandle, $Requested) { global $server; global $db; global $user; global $pass; global $sDebug; $con = mysql_connect($server,$user,$pass); I have an include file which sets those variables, as I say they work on other pages and functions.. No idea why ??

    Read the article

  • how to use replace_regex_copy() from boost::algorithm library?

    - by Vincenzo
    This is my code: #include <string> #include <boost/algorithm/string/regex.hpp> string f(const string& s) { using namespace boost::algorithm; return replace_regex_copy(s, "\\w", "?"); } This is what compiler says: no matching function for call to ‘replace_regex_copy(const std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, std::string, std::string) The link to the library: http://www.boost.org/doc/libs/1_43_0/doc/html/boost/algorithm/replace_regex_copy.html Could anyone please help? Thanks! ps. Boost library is in place, since other functions from it work fine.

    Read the article

  • When should we use * and & and . and -> ?

    - by uzay95
    Why we are using * character when we are creating button but we aren't adding it to app instance? #include <QApplication> #include <QPushButton> int main(int argc,char *argv[]) { QApplication app(argc,argv); QPushButton *button = new QPushButton("Button Text"); QObject::connect(button,SIGNAL(clicked()),&app,SLOT(quit())); button->show(); return app.exec(); } When should we use * and & and . and - ?

    Read the article

  • Segmentation fault C++ in recursive function

    - by user69514
    Why do I get a segmentation fault in my recursive function. It happens every time i call it when a value greater than 4 as a parameter #include <iostream> #include <limits> using namespace std; int printSeries(int n){ if(n==1){ return 1; } else if( n==2){ return 2; } else if( n==3){ return 3; } else if( n==4){ return printSeries(1) + printSeries(2) + printSeries(3); } else{ return printSeries(n-3) + printSeries((n-2) + printSeries(n-1)); } } int main(){ //double infinity = numeric_limits<double>::max(); for(int i=1; i<=10; i++){ cout << printSeries(i) << endl; } return 0; }

    Read the article

  • How to make a rectangle on screen invisible to screen capture ?

    - by Kesarion
    How can I create a rectangle on the screen that is invisible to any sort of screen capture(printscreen or aplications) ? By create a rectangle on screen I mean something like this: #include <Windows.h> #include <iostream> void drawRect(){ HDC screenDC = ::GetDC(0); ::Rectangle(screenDC, 200, 200, 300, 300); ::ReleaseDC(0, screenDC); } int main(void){ char c; std::cin >> c; if (c == 'd') drawRect(); std::cin >> c; return 0; } I'm using Visual Studio 2010 on Windows XP

    Read the article

  • Same memory space being allocated again & again

    - by shadyabhi
    In each loop iteration, variable j is declared again and again. Then why is its address remaining same? Shouldn't it be given some random address each time? Is this compiler dependent? #include<stdio.h> #include<malloc.h> int main() { int i=3; while (i--) { int j; printf("%p\n", &j); } return 0; } Testrun:- shadyabhi@shadyabhi-desktop:~/c$ gcc test.c shadyabhi@shadyabhi-desktop:~/c$ ./a.out 0x7fffc0b8e138 0x7fffc0b8e138 0x7fffc0b8e138 shadyabhi@shadyabhi-desktop:~/c$

    Read the article

  • C++ inheritance: scoping and visibility of members

    - by Poiuyt
    Can you explain why this is not allowed, #include <stdio.h> class B { private: int a; public: int a; }; int main() { return 0; } while this is? #include <stdio.h> class A { public: int a; }; class B : public A{ private: int a; }; int main() { return 0; } In both the cases, we have one public and one private variable named a in class B. edited now!

    Read the article

< Previous Page | 138 139 140 141 142 143 144 145 146 147 148 149  | Next Page >