[C++][백준 10828][스택] 스택 :: seoftware

문제

https://www.acmicpc.net/problem/10828

10828번: 스택

소스코드

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

stack<int> st;

int main(void) {
	int n;
	cin >> n;

	while (n > 0) {
		n--;
		string s;
		cin >> s;
		if (s == "push") {
			int x;
			cin >> x;
			st.push(x);
		}
		else if (s == "pop") {
			if (st.empty()) {
				cout << -1 << endl;
			}
			else {
				cout << st.top() << endl;
				st.pop();
			}
		}
		else if (s == "size") {
			cout << st.size() << endl;
		}
		else if (s == "empty") {
			cout << st.empty() << endl;
		}
		else if (s == "top") {
			if (st.empty()) cout << -1 << endl;
			else cout << st.top() << endl;
		}
	}
	return 0;
}

stack<int> st를 while문 안에 넣으면 안됨!! 

결과화면