C :: How To Convert Char Array Into Int Array

I am writing code to multiply two int arrays and in my one function i am trying to convert the char array into an int array. I have tested many parts however i can not find the problem.

Code:

struct integer* convert_integer(char* stringInt){
struct integer *converted = malloc(sizeof(struct integer));
int length, i, *ints;
ints = (int *)malloc(10001 * sizeof(int));
length = strlen(stringInt);
printf("stringInt: %s with length of %d
", stringInt, length);
converted->size = length;

[Code]...