题解 | #【模板】栈#

#include <iostream>
#include <string>
using namespace std;


class mystack {
  private:
    int s[100000];
    int index = 0;
  public:
    void push(int x) {
        s[index] = x;
        index++;
    }
    void pop() {
        if(index>0){
            index--;
            cout << s[index] << endl;
        }else{
            cout<<"error"<<endl;
        }

    }
    void top(){
        if(index>0){
            cout<<s[index-1]<<endl;
        }else{
            cout<<"error"<<endl;
        }
        
    }
};



    int main() {
        mystack ms;
        int input_num;
        cin>>input_num;
        while(input_num){
            string order;
            cin>>order;
            if(order=="push"){
                int inp;
                cin>>inp;
                ms.push(inp);
            }
            else if(order=="pop"){
                ms.pop();
            }
            else if(order=="top"){
                ms.top();
            }
            input_num--;
        }
        return 0;
    }
// 64 位输出请用 printf("%lld")

很基本的操作