写了一个栈模拟

#include<bits/stdc++.h>
using namespace std;
const int N=1e5+10;
int head=0;
int s[N];
bool empty(){
    if(head==0) return true;
    else return false;
}
void pop(){
    head--;
    return;
}
void push(int x){
    head++;
    s[head]=x;
    return;
}
void print(){
    printf("\n\nStack printing:\n\n");
    _sleep(500);
    if(empty()) printf("   empty\n\n");
    for(int i=head;i>=1;i--){
        printf("|    %d    |\n",s[i]);
        printf("------------\n");
        _sleep(30);
    }
    return;
}
int main(){
    printf("指令说明：empty 判断栈空，print 打印栈，pop出栈，push x 入栈x。\n\n");
    printf("Instruction description: empty determines that the stack is empty, print prints the stack, pop exits the stack, push x enters the stack.\n\n");
    while(true){
        char input[10];
        printf("input >>>");
        cin>>input;
        if(input[0]=='-' and input[1]=='1') break;
        else if(input[0]=='p' and input[1]=='o' and input[2]=='p'){
            if(!empty()) pop();
            else if(empty()) printf("\nIllegal operation: the stack is empty!\n\n");
        }
        else if(input[0]=='p' and input[1]=='u' and input[2]=='s' and input[3]=='h'){
            int x;
            scanf("%d",&x);
            push(x);
        }
        else if(input[0]=='e' and input[1]=='m' and input[2]=='p' and input[3]=='t' and input[4]=='y'){
            if(!empty()) printf("\nStack is not empty.\n\n");
            else if(empty()) printf("\nthe stack is empty.\n\n");
        }
        else if(input[0]=='p' and input[1]=='r' and input[2]=='i' and input[3]=='n' and input[4]=='t'){
            print();
        }
        else{
            printf("\nIllegal operation: Illegal input\n\n");
        }
    }
    return 0;
}