C++堆栈

用两个栈实现一个队列

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

class Solution {
private:
	stack<int> s1;
	stack<int> s2;
public:
	int pop() {
		int x;
		if (s2.empty()) {
			while (!s1.empty()) {
				s2.push(s1.top());
				s1.pop();
			}
			x = s2.top();
			s2.pop();
		}
		else {
			x = s2.top();
			s2.pop();
		}
		return x;
	}
	void push(int x) {
		s1.push(x);
	}
};


int main() {
	Solution Sol = Solution();
	Sol.push(1);
	Sol.push(2);
	Sol.push(3);
	Sol.push(4);
	cout << Sol.pop() << endl;
	Sol.push(45);
	cout << Sol.pop() << endl;
	cout << Sol.pop() << endl;
	cout << Sol.pop() << endl;
	cout << Sol.pop() << endl;
}