push pop の練習

push&pop.c

#include <stdio.h>
#define N 100

int sp = 0;
int a[N];

void push(int b){
    if (sp < N)
        a[sp++] = b;
    else
        printf("Error: stack is full\n");
}

int pop(){
    if (sp > 0)
        return a[--sp];
    else
        printf("Error: stack is empty\n");
    return 0;
}

int main(){
    for (int i = 0; i < 50; ++i)
        push(i);

    for (int i = 0; i < 50; ++i)
        printf("%d\n", a[i]);
    printf("====================\n");
    for (int i = 0; i < 50; ++i)
        printf("%d\n", pop());

}