我输出的结果是3,正确的结果应该是1,2,3才对。我写错了吗?求指教
#include<stack>
#include<iostream>
int main(){
stack<int> s1, s2;
s1.push(1);
s1.push(2);
s1.push(3);
if (!s1.empty()) {
s2.push(s1.top());
s1.pop();
}
while (!s2.empty())
{
cout << s2.top();
s2.pop();
}
}
原题是用两个栈实现队列:
#pragma
#include "pch.h"
#include <iostream>
#include<stack>
using namespace std;
//无需任何边界检查,因为STL已经帮你把工作做完了
class StackToQueue {
public:
StackToQueue(stack<int> st1, stack<int> st2) : s1(st1), s2(st2) {};
StackToQueue() = default;
void pop(); //出队
void push(int v);//入队
int top();//获取队首元素
size_t length();//返回当前队的长度
private:
stack<int> s1;
stack<int> s2;
};
void StackToQueue::pop()
{
while (!s1.empty()) {
s2.push(s1.top());
s1.pop();
}
s2.pop();
while (!s2.empty()) {
s1.push(s2.top());
s2.pop();
}
}
void StackToQueue::push(int v)
{
s1.push(v);
}
int StackToQueue::top()
{
while (!s1.empty())
{
s2.push(s1.top());
s1.pop();
}
int temp = s2.top();
while (!s2.empty())
{
s1.push(s2.top());
s2.pop();
}
return temp;
}
size_t StackToQueue::length()
{
return s1.size();
}