Question

I have been asked to upload my four programs which at the moment are running fine separately but I have been asked to submit my work in one C file. My concern is that they share similar variables, is it even possible to have one program run then close and then the second one without interference.

Answer 1

If they don’t use global variables, sure:

int main(int argc, char *argv[])
{
    first(argc, argv);
    second(argc, argv);
    /* etc. */
}

int first(int argc, char * argv[]) /* formerly known as main() */
{
}

int second(int argc, char * argv[]) /* likewise */
{
}