“this” pointer in C (not C++)

Question

I\'m trying to create a stack in C for fun, and came up with the idea of using struct to represent the stack. Then I add function pointers to the struct for push() and pop()

Answer 1

There's no implicit this in C. Make it explicit:

int push(Stack* self, int val) {
    if(self->current_size == self->max_size - 1)
            return 0;

    self->data[self->current_size] = val;
    (self->current_size)++;

    return 1;
}

You will of course have to pass the pointer to the struct into every call to push and similar methods.

This is essentially what the C++ compiler is doing for you when you define Stack as a class and push et al as methods.