Question

I am working on a small C application and I am capturing a value from the command line. I would like to capture the value and use it to initialize an array. Here is what I’m trying to do.

int main(int argc, char* argv[]) {
    int option = atoi(argv[2]);
    int values[option];
    ......
 }

I am getting a compilation because my option variable is not a const.
Error: Error 2 error C2057: expected constant expression

Is there a way I can do this?

Thanks for your help!

Answer 1

If the size is not known at compile-time, you need to allocate the memory dynamically, with malloc:

 int main(int argc, char* argv[]) {
    int option = atoi(argv[2]);
    int* values = malloc(option * sizeof(int));
    /* ...... */
    free(values); /* Deallocate the memory when you are done with it */
 }