#include <stdio.h>

#define SIZE 5

int stack[SIZE];
int sp = 0;

void push(int x) {
    if (sp < SIZE) {
        stack[sp] = x;
        sp++;
    }
}

int pop(void) {
    if (sp > 0) {
        sp--;
        return stack[sp];
    }
    return -1;
}

int main(void) {
    int data[] = {11, 12, 13, 14, 15};
    int n = 5;

    for (int i = 0; i < n; i++) {
        push(data[i]);
    }

    for (int i = 0; i < n; i++) {
        data[i] = pop();
    }

    for (int i = 0; i < n; i++) {
        printf("%d ", data[i]);
    }
    printf("\n");

    return 0;
}