stack.c

#include <stdio.h>
#include <stdlib.h>

#define MAX_DEPTH 100

int top = -1;
int stack[MAX_DEPTH];

char pop();
char pop() {
  int value = stack[top];
  top -= 1;
  printf("inside pop! top %d, value: %d\n", top, value);
  return value;
}

void push(int c);
void push(int c) {
  stack[++top] = c;
  printf("inside pushed! top %d, value: %d\n", top, stack[top]);
}

int value2;
int main() {
  push(2);
  push(400);

  value2 = pop();
  printf("pop! %d\n", value2);

  value2 = pop();
  printf("pop! %d\n", value2);

  return 0;
}

/*
  Print
inside pushed! top 0, value: 2
inside pushed! top 1, value: 400
inside pop! top 0, value: 400
pop! -112 <<--- WTF?
inside pop! top -1, value: 2
pop! 2

*/