我用的STL

#include<bits/stdc++.h>
using namespace std;
int main() {
	string a;
	stack<int> b;
	int c;
	int n, m;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> m;
		for (int j = 0; j < m; j++) {
			cin >> a;
			if (a == "push") {
				cin >> c;
				b.push(c);
			} else if (a == "pop") {
				if (b.empty()) {
					cout << "Empty" << endl;
				} else {
					b.pop();
				}
			} else if (a == "query") {
				if (b.empty()) {
					cout << "Anguei!" << endl;
				} else {
					cout << b.top() << endl;
				}
			} else if (a == "size") {
				cout << b.size() << endl;
			}
		}
	}
	return 0;
}