[gameprogrammer] Re: passing pointer to array

I think your program is confused regarding pointers and pointers to pointers. I think you need something like the following: 

int fileToArray(stf::string filename, int **numbers, int* len) {
 /* ... */
 num_integers = ... /* read number of integers from the file */
 *numbers = (int*)malloc(sizeof(int) * num_integers);
 *len = num_integers;
 /* read the integers from the file */
}

main() {
 int len;
 int *numbers;
 if (fileToArray(filename, &numbers, &len)) {
   for(int i = 0; i < len; ++i){
     std::cout<<numbers[i];
   }
 }
}

Note different prototype for fileToArray.

All the best,

Andy

Christoph Harder wrote:

Hello,
I'm currently writing a mergesort for school (yes i know nothing directly related to gamedev but maybe you can help) and got a bit confused. 

I have a pointer (in the main-function): int *numbers = 0;

a function for reading int values from a file:
int fileToArray(std::string filename, int *numbers, int &len);
in the function i allocate memory for the numbers:
numbers = new int[len];

I want to use both the length and the numbers in the main function,
but when I try to print them i get either an exeption, or the memory adresse: 
for(int i = 0; i < len; ++i){
   std::cout<<numbers[i]; //exeption
   //std::cout<<&numbers[i]; //strange output (propably the adresses)
}

This is how i call the function:
if(fileToArray(filelist[fi], numbers, len))
{...}

Can anybody please tell me what I have done wrong?

Thanks in advance
Christoph




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