#include <stdio.h>
#define SIZE 5

int stack[SIZE];
int sp;

void push(int value) {
    if (sp < SIZE) {
        stack[sp++] = value;
    } else {
        printf("Stack Overflow\n");
    }
}

int pop(void) {
    if (sp > 0) {
        return stack[--sp];
    } else {
        printf("Stack Underflow\n");
        return -1;
    }
}

int main(void) {
    sp = 0;
    int resp, data;

    while (1) {
        printf("1:push 2:pop 0:end : ");
        scanf("%d", &resp);

        if (!resp) break;

        switch (resp) {
            case 1: 
                printf("push : "); 
                scanf("%d", &data);
                push(data);
                break;
            case 2: 
                pop();
                break;
        }

        printf("\n");
        for (int i = 0; i < sp; i++) {
            printf("stack[%d]=%d\n", i, stack[i]);
        }
    } // ← ここに while を閉じるカッコが必要です

    return 0;
}