Hi I wrote a C code that a portion of it is: ... P *head=NULL,*cur=NULL; char Name,tmp[255]; int AT,ET; FILE *iF; if((iF=fopen(fileName,"r"))>0){ fgets(tmp,255,iF); sscanf(tmp,"Interval:%d\n",&quantum); fgets(tmp,255,iF); //waste while(!feof(iF) && fgets(tmp,255,iF)){ ...
Hello, how can I pass multiarray into function through pointer with c++. I can do this with simple arrays void Foo(int *arr) { } int someArr[10]; Foo(someArr); What about 2-dimensions array? ...
Hi, I have a very simple question. I want to write the below line of code in 2 lines : IplImage *image = 0; like : IplImage *image; image = 0; I want to know what I have written is correct or else I want to know how to write the correct one (in two lines). Thanks ...
The following program compiles with g++ but then crashes upon running: class someClass { public: int const mem; someClass(int arg):mem(arg){} }; int main() { int arg = 0; someClass ob(arg); float* sample; *sample = (float)1; return 0; } The following program does not crash: int main() { float* samp...
I currently have code for a subroutine to return a pointer to an array. This array is a list of random numbers for a one dimensional monte-carlo integral. I am now trying to do a multi dimensional equivalent which requires 3 arrays of random numbers and instead of having a separate subroutine for each I'm trying to make one which retur...
I have a pointer to an array, DI. Is it possible to go to the value pointed to by both DI and another pointer? e.g: mov bl,1 mov bh,10 inc [di+bl] inc [di+bh] And, on a related note, is there a single line opcode to swap the values of two registers? (In my case, BX and BP?) ...
Is the following code 100% portable? int a=10; size_t size_of_int = (char *)(&a+1)-(char*)(&a); // No problem here? std::cout<<size_of_int;// or printf("%zu",size_of_int); P.S: The question is only for learning purpose. So please don't give answers like Use sizeof() etc ...
I ran into my first compiler that changes the lvalue passed to ::delete, but doesn't zero out the lvalue. That is the following is true: Foo * p = new Foo(); Foo * q = p; assert(p != 0); assert(p == q); ::delete p; assert(p != q); assert(p != 0); Note that p is not zero after the delete operation, and it has changed from it's o...
I have two arrays of pointers to doubles that I need to swap. Rather than just copy the data within the arrays, it would be more efficient just to swap the pointers to the arrays. I was always under the impression that array names were essentially just pointers, but the following code receives a compiler error: double left[] = {1,2,3}; ...
Possible Duplicate: Why is this C code causing a segmentation fault? char* string = "abcd"; now when i try to change some character of this string i get segmentation fault *string = 'p'; or string[0] = 'p'; string[0] = 52; Can someone please explain me the reason that why is it happening. Thanks Alok.Kr. ...
hey folks, why does this: char** pointer = new char*[1]; std::cout << sizeof(pointer) << "\n"; output 4? I have an array of pointers, but it should have length 1, shouldn't it? ...
Hello, gcc 4.4.4 c89 In main I call a function to pass a line of text to a function. I want to perform some operation on it. However, that would mean that line is of no use. So in my get_string function I copy the contents and return the result. The only problem, is that the memory to that result would be lost and pointing to something...
I just simply release objects as such: [myObj release]; I have seen others add: [myObj release]; myObj = nil; Is the latter more advantageous because now there will never be a reference to that pointer? ...
What will be the behavior and output of the following code if i accidentally code so in C/C++, float a = 12.5; printf("%d\n", a); printf("%d\n", *(int *)&a); ...
Why does the following program give a warning? Note: Its obvious that sending a normal pointer to a function requiring const pointer does not give any warning. #include <stdio.h> void sam(const char **p) { } int main(int argc, char **argv) { sam(argv); return 0; } I get the following error, In function `int main(int, char **...
Hello, I have a 2 dimensional array dynamically allocated in my C code, in my function main. I need to pass this 2D array to a function. Since the columns and rows of the array are run time variables, i know one way to pass it is : -Pass the rows,column variables and the pointer to that [0][0] element of the array myfunc(&arr[0][0],r...
Hi there, I'm stuck with a weird problem. I have two files a.c and b.c as follows: b.c: #include <stdlib.h> int *foo() { int *x; x = (int *) malloc(sizeof(int)); *x = 4; return x; } I compile b.c to b.so using gcc: $ gcc -o b.so -shared -fpic a.c: #include <stdio.h> #include <dlfcn.h> int main() { void *hdl; hdl = dlop...
class someClass { public: int* ptr2Int; }; Is this a valid class (yes it compiles)? Provided one assigns a value to ptr2Int before dereferencing it, is the class guaranteed to work as one would expect? ...
I was expecting the second assert in the following to pass. I'm asking for your help. Edit: It didn't work when I had poss everywhere instead of poss_a in some places. #include <vector> #include <cassert> class Sampler { public: std::vector<int*> poss; std::vector<int*>::const_iterator poss_it; Sampler(std::vector<int*> poss_a) : ...
So, I have some function returning a pointer, or NULL on error. Now I'd like to add another possible value for a different error/condition. I heard this mentioned in some other answer before - using malloc() to create a unique pointer that will serve as a possible value for such functions to return (so now the can return a proper pointer...