题解 | #【模板】栈#

#include <iostream>
using namespace std;
int main() 
{
    int n;
    int sum=-1;
    int y;
    cin>>n;
    int stack[n];
    while(n--)
    {
        string x;
        cin>>x;
        if(x=="push")
        {
            cin>>y;
            stack[++sum]=y;
        }
        else if(x=="top")
        {
             if(sum<0)
            {
                cout<<"error"<<endl;
                continue;
            }
        cout<<stack[sum]<<endl;
        }
       else if(x=="pop")
        {
            if(sum<0)
            {
                cout<<"error"<<endl;
                continue;
            }
            cout<<stack[sum--]<<endl;
        }
    }
return 0;
}
  
// 64 位输出请用 printf("%lld")

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