#include <stdio.h>

int stackTop = -1;
int stackData[100];

void push(int x)
{
   // check if stack is not full. 
   if ( stackTop < 100 )
   {
      stackData[++stackTop] = x;
   }
}

int pop( )
{
   // check if stack is not empty
   if ( stackTop > -1 )
   {    
      return( stackData[stackTop--] );
   }

   return (-999999); // Pop empty stack error
}