Question

I have a problem with strcpy function. Using C.
Main point of this simple code (below) is copying a string from a array to the array of pointers.

char string[20] = "ABCDEFGH\0";
char * array_of_pointers[20];

// now I want to copy string to the first available slot;

strcpy(array_of_pointers[0],string);

Then strcpy throws me error:

Unhandled exception: Access violation writing location 0x00000000.

Why? I know that this problem is probably simple, but I really don’t have a clue.

Answer 1

The target buffer has not been initialized. array_of_pointers[0] is just a pointer that (in this case based on the error information from the access violation) points to address 0. You need to initialize it. Possibly:

array_of_pointers[0] = malloc( strlen( string ) + 1 );

array_of_pointers is an array of 20 pointers. Defined like that, each entry in that array must be initialized before it can be used. Remember too that if you do use malloc (or possibly strdup) to allocate the memory, use free to release the memory.