Question

As the title says, how do I use the pointer of a function in C? Can I just take the address of the function name and pass it to another function; then dereference it and call it?

Thanks a lot.

Answer 1

If you know the function address, then yes. For example:

int add(int a, int b)
{
    return a + b;
}

int sub(int a, int b)
{
    return a - b;
}

int operation(int (*op)(int, int), int a, int b)
{
    return op(a, b);
}

Then just call it like this:

printf("%d\n", operation(&add, 5, 3)); // 8
printf("%d\n", operation(&sub, 5, 3)); // 2

You can even do some array tricks:

int op = 0;
int (*my_pointer[2])(int, int) =
{
    add, // op = 0 for add
    sub  // op = 1 for sub
};
printf("%d\n", my_pointer[op](8, 2)); // 10