#include <assert.h>

struct IntStack
{
    bool (*push)(int data, IntStack&);
    bool (*pop)(int &data, IntStack&);
    int top;
    int data[1000];
};

bool push(int value, IntStack &stack)
{
    if (stack.top >= 1000)
        return false;
    else
    {
        stack.data[stack.top++] = value;
        return true;
    }
}

bool pop(int &value, IntStack &stack)
{
    if (stack.top <= 0)
        return false;
    else
    {
        value = stack.data[--stack.top];
        return true;
    }
}

void main()
{
    int i, value;
    IntStack theStack = {push, pop, 0};

    for (i=0; i<10; i++)
        assert(theStack.push(i, theStack));

    for (i=0; i<10; i++)
    {
        assert(theStack.pop(value, theStack));
        assert(value == 9-i);
    }
}