Q3.6 sort a stack in ascending order

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Q:Write a program to sort a stack in ascending order. You should not make any assumptions about how the stack is implemented. The following are the only functions that should be used to write this program: push | pop | peek | isEmpty.

A: 再利用另外一个栈来模拟插入排序。 sin是原来的栈，sout是用来储存排序后的栈,

将sin.top() 元素保存在一个临时变量tmp里面，同sout中的元素比较，如果大于sout的top元素，那么就压入当前位置，否则将sout的top元素压入sin之中，tmp继续与sout的top比较，直到sout为空。

#include <iostream>#include <stack> using namespace std;stack<int> sortStack(stack<int> s) {stack<int> t;if (s.empty()) {return t;}t.push(s.top());s.pop();while (!s.empty()) {int tmp = s.top();s.pop();while (!t.empty() && t.top() > tmp) {s.push(t.top());t.pop();}t.push(tmp);}return t;}int main() {int a[5] = {3,5,2,4,1};stack<int> s;for (int i = 0; i < 5; i++) {s.push(a[i]);}while (!s.empty()) {cout<<s.top()<<" ";s.pop();}cout<<endl;for (int i = 0; i < 5; i++) {s.push(a[i]);}s = sortStack(s);while (!s.empty()) {cout<<s.top()<<" ";s.pop();}cout<<endl;return 0;}

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