Dereference a pointer inside a structure pointer
- by klez
I have a structure:
struct mystruct
{
int* pointer;
};
structure mystruct* struct_inst;
Now I want to change the value pointed to by struct_inst->pointer. How can I do that?
Search Results
Search found 5789 results on 232 pages for 'smart pointer'.
Page 4/232 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12 | Next Page >
-
-
Smart pointers and polymorphism
- by qwerty
hello. I implemented reference counting pointers (called SP in the example) and im having problems with polymorphism which i think i shouldn't have. In the following code: SP<BaseClass> foo() { // Some logic... SP<DerivedClass> retPtr = new DerivedClass(); return retPtr; } DerivedClass inherits from BaseClass. With normal pointers this should have worked, but with the smart pointers it says "cannot convert from 'SP<T>' to 'const SP<T>&" and i think it refers to the copy constructor of the smart pointer. How to i allow this kind of polymorphism with reference counting pointer? I'd appreciate code samples cause obviously im doing something wrong here if im having this problem. Thanks! :) [p.s., plz don't tell me to use standart liberary with smart pointers cuz that's impossible at this moment.]Read the article
-
Detecting Visual Studio Smart-tags events
- by devoured elysium
Is it possible to detect with VSX when any (or a particular) smart tag event is happening? I mean, every time we rename a variable, for example, a smart tag is available that allows us to change it through a form. I'd like to know if I can access that "text is changing" event. I don't mean to have to check for myself if the text is being changed and such, I'd like to make use of VS event system (if there is one). I gave this example but I'd like to know the "general system" of how smart tags work with VSX. ThanksRead the article
-
pointer-to-pointer of derived class in multiple inheritance
- by Abdul jalil
i have 3 classes A,B and C. C is derived from A and B. i get pointer to pointer of class C and cast to A** , and B ** , the variable that hold the the B** has the address of A** in my example B ** BdoublePtr hold the address of A** .i am using the following code #include "conio.h" #include "stdio.h" #include "string.h" class A{ public: A() { strA=new char[30]; strcpy(strA,"class A"); } char *strA; }; class B { public: B() { strB=new char[30]; strcpy(strB,"class B"); } char *strB; }; class C :public A, public B { public: C() { strC=new char[30]; strcpy(strC,"class C"); } char *strC; }; int main(void) { C* ptrC=new C(); A * Aptr=(A*)ptrC; printf("\n class A value : %s",Aptr-strA); B * Bptr=(B*)ptrC; printf("\n class B value :%s",Bptr-strB); printf("\n\nnow with double pointer "); A ** AdoublePtr=(A **)&ptrC; Aptr=AdoublePtr; printf("\n class A value : %s",Aptr-strA); B * BdoublePtr=(B **)&ptrC; Bptr=*BdoublePtr; printf("\n class B value : %s",Bptr-strB); getch(); return 0; }Read the article
-
C++, function pointer to the template function pointer
- by Ian
I am having a pointer to the common static method class MyClass { private: static double ( *pfunction ) ( const Object *, const Object *); ... }; pointing to the static method class SomeClass { public: static double getA ( const Object *o1, const Object *o2); ... }; Initialization: double ( *MyClass::pfunction ) ( const Object *o1, const Object *o2 ) = &SomeClass::getA; I would like to convert this pointer to the static template function pointer: template <class T> static T ( *pfunction ) ( const Object <T> *, const Object <T> *); //Compile error where: class SomeClass { public: template <class T> static double getA ( const Object <T> *o1, const Object <T> *o2); ... }; But there is some error... Thanks for your help...Read the article
-
pointer to a pointer in a linked list
- by user1596497
I'm trying to set a linked list head through pointer to a pointer. I can see inside the function that the address of the head pointer is changing but as i return to the main progran it becomes NULL again. can someone tell me what I'm doing wrong ?? #include <stdio.h> #include <stdlib.h> typedef void(*fun_t)(int); typedef struct timer_t { int time; fun_t func; struct timer_t *next; }TIMER_T; void add_timer(int sec, fun_t func, TIMER_T *head); void run_timers(TIMER_T **head); void timer_func(int); int main(void) { TIMER_T *head = NULL; int time = 1; fun_t func = timer_func; while (time < 1000) { printf("\nCalling add_timer(time=%d, func=0x%x, head=0x%x)\n", time, func, &head); add_timer(time, func, head); time *= 2; } run_timers(&head); return 0; } void add_timer(int sec, fun_t func, TIMER_T *head) { TIMER_T ** ppScan=&head; TIMER_T *new_timer = NULL; new_timer = (TIMER_T*)malloc(sizeof(TIMER_T)); new_timer->time = sec; new_timer->func = func; new_timer->next = NULL; while((*ppScan != NULL) && (((**ppScan).time)<sec)) ppScan = &(*ppScan)->next; new_timer->next = *ppScan; *ppScan = new_timer; }Read the article
-
Excel Smart Find and Replace only specific characters
- by Asim
I want to change INT to INTERNATIONAL and NA to NATIONAL ASSEMBLY in whole excel workbook through an excel Macro or Find and Replace dialogue box. But when I run the macro or change it through Find and Replace dialogue box it also replace NA from CHINA last 2 characters and it became CHINATIONAL ASSEMBLY and INTERIOR to INTERNATIONALERIOR. Now, I want that Excel should only smartly find the character NA in the workbook which is not included with any other character likewise character INT which is not attach to any other character. I would be grateful if anyone give any formula, Excel Macro or anything else to overcome this issue. Thanks,Read the article
-
Ubuntu 14.04 disk utility SMART self-test failed threshold not exceeded
- by user2323470
I'm using the "Disks" program in Ubuntu 14.04 (live DVD) to assess the health of a drive I suspect is failing. However, when I first opened the program, it showed that the overall health was OK and all assessments are OK as well. I then tried to run a short self-test, but now the overall assessment shows a red "SELF-TEST FAILED". In the details section it says "Last self-test failed (read)" and "threshold not exceeded". All individual assessments are still OK though!! What I don't understand is, does that mean that the test executed and determined that the drive is a goner, or does it mean that the test didn't actually execute properly?Read the article
-
Reliability of S.M.A.R.T.?
- by Mark
I've been using ActiveSmart to monitor my hard-drives health for a few weeks now, and its telling me my brand new 1.5 TB hard-drive is half-dead already. About on-par with one of my hard-drives which I know is at least half dead because I've been having some read errors and heard ticking noises. Now I haven't actually noticed any problems with my 1.5 TB drive; should I be concerned that it's going to crap out on me too? Or could ActiveSmart be giving a mis-diagnosis because I use it a lot or something (I've used up 795 GB in the 2 and a half weeks I've had it). The events that ActiveSmart has been catching is "Hardware ECC recovered". Maybe these new fangled super big hard-drives somehow rely on ECCs to squeeze out the extra space, but this isn't actually a cause for concern?Read the article
-
SMART says disk failure is imminent due to bad blocks, what do I need to do?
- by flix
I have on my hard drive 2 OSes: Ubuntu 12.04 and Windows Vista (I keep it just because of school). Everything was OK on both OSes, but one day on Ubuntu I was getting awkward noises from my notebooks' hard drive and then everything stopped and I couldn't do anything. On Windows everything was OK. Every time I boot Ubuntu I can get 5 minutes normal run time, without problems. After that the hard drive sounds crazy and nothing works. I could run S.M.A.R.T tests from a older Ubuntu CD (10.04) from the GUI (Disk Utility, or something like that and from terminal). From the GUI, I got that the DISK FAILURE IS IMMINENT and I have ~700 bad blocks (or broken blocks, I had that test I while ago) on my HDD. From the terminal (I don't remember if it was fsck or a SMART test command) I got that the HDD will fail in under 24 hours. Since then it passed 2-3 weeks. I've tried "badblocks" but after 10 hours it was still running and I had to stop it. Now I have to use cygwin and other alternatives for my Linux apps on Windows. How can I separate the bad blocks from Ubuntu so it wouldn't use them? Please help.Read the article
-
Pointer initialization
- by SoulBeaver
Sorry if this question has been asked before. On my search through SO I didn't find one that asked what I wanted to know. Basically, when I have this: typedef struct node { int data; node *node; } *head; and do node *newItem = new node; I am under the impression that I am declaring and reserving space, but not defining, a pointer to struct node, is that correct? So when I do newItem->data = 100 and newItem->next = 0 I get confused. newItem = 0would declare what exactly? Both data and next? The object as a whole? I'm especially confused when I use typedef. Which part is the macro? I assume node because that's how I call it, but why do I need it? Finally, what happens when I do: node *temp; temp = new node; temp = head->next; head->next = newItem; newItem->next = temp; I mean, head-next is a pointer pointing to object newItem, so I assume not to newItem.data or next themselves. So how can I use an uninitialized pointer that I described above safely like here? is head now not pointing to an uninitialized pointer?Read the article
-
c program pointer
- by sandy101
Hello , I am trying some programs in c face a problem with this program #include<stdio.h> int main() { int a=9,*x; float b=3.6,*y; char c='a',*z; printf("the value is %d\n",a); printf("the value is %f\n",b); printf("the value is %c\n",c); x=&a; y=&b; z=&c; printf("%u\n",a); printf("%u\n",b); printf("%u\n",c); x++; y++; z++; printf("%u\n",a); printf("%u\n",b); printf("%u\n",c); return 0; } can any one tell me what is the problem with this and i also want to know that when in the above case if the pointer value is incremented then will it over write the previous value address as suppose that the value we got in the above program (without the increment in the pointer value )is 65524 65520 65519 and after the increment the value of the pointer is 65526(as 2 increment for the int ) 65524(as 4 increment for the float ) 65520(as 1 increment for the char variable ) then if in that case will the new pointer address overwrite the content of the previous address and what value be contained at the new address ......plz helpRead the article
-
What is the use of Pointer to Pointer?
- by hiral
Why do we need a double pointer? What are some examples or use cases?Read the article
-
Why implement DB connection pointer object as a reference counting pointer? (C++)
- by DVK
At our company one of the core C++ classes (Database connection pointer) is implemented as a reference counting pointer. To be clear, the objects are NOT DB connections themselves, but pointers to a DB connection object. The library is very old, and nobody who designed is around anymore. So far, nether I, nor any C++ experts in the company that I asked have come up with a good reason for why this particular design was chosen. Any ideas? It is introducing some problems (partially due to awful reference pointer implementation used), and I'm trying to understand if this design actually has some deep underlying reasons? The usage pattern these days seems to be that the DB connection pointer object is returned by a DB connection manager class, and it's somewhat unclear whether DB connection pointers were designed to be able to be used independently of DB connection manager.Read the article
-
commands&creating pointer [closed]
- by gcc
input 23 3 4 4 42 n 23 0 9 9 n n n 3 9 9 x //according to input,i should create int pointer arrays. pointer arrays // starting from 1 (that is initial arrays is arrays[1].when program sees n ,it // must be jumb to arrays 2 // the first int input 23 is num_arrays which used in malloc(sizeof(int)*num_arrays expected output: elements of arrays[1] 3 4 5 42 elements of arrays[2] 23 0 9 9 elements of arrays[5] 3 9 9 another input 12 2 3 4 n n 2 3 4 n 12 3 x expected output elements of arrays[1] 2 3 4 elements of arrays[3] 2 3 4 elements of arrays[4] 12 3 specification: x is stopper n is comman to create new pointer array i am new in this site anyone help me how can i writeRead the article
-
n & x commands&creating pointer&with using malloc [closed]
- by gcc
input 23 3 4 4 42 n 23 0 9 9 n n n 3 9 9 x //according to input,i should create int pointer arrays. pointer arrays // starting from 1 (that is initial arrays is arrays[1].when program sees n ,it // must be jumb to arrays 2 // the first int input 23 is num_arrays which used in malloc(sizeof(int)*num_arrays expected output arrays[1] 3 4 5 42 arrays[2] 23 0 9 9 arrays[5] 3 9 9 another input 12 2 3 4 n n 2 3 4 n 12 3 x expected output arrays[1] 2 3 4 arrays[3] 2 3 4 arrays[4] 12 3 x is stopper n is comman to create new pointer array i am new in this site anyone help me how can i writeRead the article
-
Question on Pointer Arithmetic
- by pws5068
Heyy Everybody! I am trying to create a memory management system, so that a user can call myMalloc, a method I created. I have a linked list keeping track of my free memory. My problem is when I am attempting to find the end of a free bit in my linked list. I am attempting to add the size of the memory free in that section (which is in the linked list) to the pointer to the front of the free space, like this. void *tailEnd = previousPlace->head_ptr + ((previousPlace->size+1)*(sizeof(int)); I was hoping that this would give me a pointer to the end of that segment. However, I keep getting the warning: "pointer of type 'void*' used in arithmetic" Is there a better way of doing this? Thanks!Read the article
-
"Initializing" the pointer in the separate function in C
- by pechenie
I need to do a simple thing, which I used to do many times in Java, but I'm stuck in C (pure C, not C++). The situation looks like this: int *a; void initArray( int *arr ) { arr = malloc( sizeof( int ) * SIZE ); } int main() { initArray( a ); // a is NULL here! what to do?! return 0; } I have some "initializing" function, which SHOULD assign a given pointer to some allocated data (doesn't matter). How should I give a pointer to a function in order to this pointer will be modified, and then can be used further in the code (after that function call returns)? Thanx for help.Read the article
-
Smart defaults [SSDT]
- by jamiet
I’ve just discovered a new, somewhat hidden, feature in SSDT that I didn’t know about and figured it would be worth highlighting here because I’ll bet not many others know it either; the feature is called Smart Defaults. It gets around the problem of adding a NOT NULLable column to an existing table that has got data in it – previous to SSDT you would need to define a DEFAULT constraint however it does feel rather cumbersome to create an object purely for the purpose of pushing through a deployment – that’s the situation that Smart Defaults is meant to alleviate. The Smart Defaults option exists in the advanced section of a Publish Profile file: The description of the setting is “Automatically provides a default value when updating a table that contains data with a column that does not allow null values”, in other words checking that option will cause SSDT to insert an arbitrary default value into your newly created NON NULLable column. In case you’re wondering how it does it, here’s how: SSDT creates a DEFAULT CONSTRAINT at the same time as the column is created and then immediately removes that constraint: ALTER TABLE [dbo].[T1] ADD [C1] INT NOT NULL, CONSTRAINT [SD_T1_1df7a5f76cf44bb593506d05ff9a1e2b] DEFAULT 0 FOR [C1];ALTER TABLE [dbo].[T1] DROP CONSTRAINT [SD_T1_1df7a5f76cf44bb593506d05ff9a1e2b]; You can then update the value as appropriate in a Post-Deployment script. Pretty cool! On the downside, you can only specify this option for the whole project, not for an individual table or even an individual column – I’m not sure that I’d want to turn this on for an entire project as it could hide problems that a failed deployment would highlight, in other words smart defaults could be seen to be “papering over the cracks”. If you think that should be improved go and vote (and leave a comment) at [SSDT] Allow us to specify Smart defaults per table or even per column. @JamietRead the article
-
SMART Technologies E-Business Suite Release 12 Success
Get smart about E-Business Suite Release 12 implementation with this customer success story. Hear Mike Battistel, VP Information Systems – SMART Technologies, discuss why they selected E-Business Suite Release 12, the implementation process, what benefits they have gained and lessons learned along the way. SMART Technologies is both the industry pioneer and market-segment leader in easy-to-use interactive whiteboards and other group collaboration tools.Read the article
-
Smart defaults [SSDT]
- by jamiet
I’ve just discovered a new, somewhat hidden, feature in SSDT that I didn’t know about and figured it would be worth highlighting here because I’ll bet not many others know it either; the feature is called Smart Defaults. It gets around the problem of adding a NOT NULLable column to an existing table that has got data in it – previous to SSDT you would need to define a DEFAULT constraint however it does feel rather cumbersome to create an object purely for the purpose of pushing through a deployment – that’s the situation that Smart Defaults is meant to alleviate. The Smart Defaults option exists in the advanced section of a Publish Profile file: The description of the setting is “Automatically provides a default value when updating a table that contains data with a column that does not allow null values”, in other words checking that option will cause SSDT to insert an arbitrary default value into your newly created NON NULLable column. In case you’re wondering how it does it, here’s how: SSDT creates a DEFAULT CONSTRAINT at the same time as the column is created and then immediately removes that constraint: ALTER TABLE [dbo].[T1] ADD [C1] INT NOT NULL, CONSTRAINT [SD_T1_1df7a5f76cf44bb593506d05ff9a1e2b] DEFAULT 0 FOR [C1];ALTER TABLE [dbo].[T1] DROP CONSTRAINT [SD_T1_1df7a5f76cf44bb593506d05ff9a1e2b]; You can then update the value as appropriate in a Post-Deployment script. Pretty cool! On the downside, you can only specify this option for the whole project, not for an individual table or even an individual column – I’m not sure that I’d want to turn this on for an entire project as it could hide problems that a failed deployment would highlight, in other words smart defaults could be seen to be “papering over the cracks”. If you think that should be improved go and vote (and leave a comment) at [SSDT] Allow us to specify Smart defaults per table or even per column. @JamietRead the article
-
Smart Meter Management on the NetBeans Platform
- by Geertjan
Netinium® NCC is the operator console for the Netinium® AMM+ platform, a Head End system for multi-vendor smart meter and smart grid infrastructures. The role based NCC provides a uniform operations environment for grid operators and utilities to securely manage millions of smart meters, in-home displays and other smart devices using different types of communication networks such as IP, PLC, GPRS, CDMA and BPL. Based on the NetBeans Platform, the NCC offers the flexibility to easily extend the GUI with new functionality when new devices are added to the system. For more information visit http://www.netinium.com.Read the article
-
Developing Games for Samsung Smart TV
- by Caner Öncü
We are planning to develop a game for Samsung Smart TVs. Although those TVs support Flash and HTML5 other specs fail at supporting a game engine. For ex: Using an engine that needs GPU is not possible with the default Samsung smart tv set. Or... WebGL is supported with Samsung SDK 4.1 but we don't know if SDK 4.1 is available for Smart TV series between 7000-9000 or not. We have tried to communicate with Samsung but they don't really seem to respond. Is there anyone who has developed a game for Samsung Smart TVs? If there is, can you name the game engines that can work with those TVs?Read the article
-
Passing NSArray Pointer Rather Than A Pointer To a Specific Type
- by mattmccomb
I've just written a piece of code to display a UIActionSheet within my app. Whilst looking at the code to initialise my UIActionSheet something struck me as a little strange. The initialisation function has the following signature... initWithTitle:(NSString *)title delegate:(id UIActionSheetDelegate)delegate cancelButtonTitle:(NSString *)cancelButtonTitle destructiveButtonTitle:(NSString *)destructiveButtonTitle otherButtonTitles:(NSString *)otherButtonTitles As you can see the otherButtonTitles parameter is a pointer to a String. In my code I set it as follows... otherButtonTitles: @"Title", @"Date", nil Although this compiles fine I don't really understand how it works. My reading of the statement is that I have created an inline array containing two elements (Title and Date). How come this then compiles? I'm passing a NSArray* in place of a NSString*. I know from a little of understanding of C++ that an array is really a pointer to the first element. So is this inline array that I'm creating a C array as opposed to a NSArray? What I'm hoping to achieve is to be able to pass a static NSArray* used elsewhere in my class to the otherButtonTitles parameter. But passing the NSArray* object directly doesn't work.Read the article
-
Normal pointer vs Auto pointer (std::auto_ptr)
- by AKN
Code snippet (normal pointer) int *pi = new int; int i = 90; pi = &i; int k = *pi + 10; cout<<k<<endl; delete pi; [Output: 100] Code snippet (auto pointer) Case 1: std::auto_ptr<int> pi(new int); int i = 90; pi = &i; int k = *pi + 10; //Throws unhandled exception error at this point while debugging. cout<<k<<endl; //delete pi; (It deletes by itself when goes out of scope. So explicit 'delete' call not required) Case 2: std::auto_ptr<int> pi(new int); int i = 90; *pi = 90; int k = *pi + 10; cout<<k<<endl; [Output: 100] Can someone please tell why it failed to work for case 1?Read the article
