面试金典--17.1

题目描述：不用临时变量，直接交换两个数

思路

a = a+b;b = a- b;a = a-b

#include <iostream>
#include <queue>
#include <climits>
#include <algorithm>
#include <memory.h>
#include <stdio.h>
#include <ostream>
#include <vector>
#include <list>
#include <cmath>
#include <string>
#include <stdexcept>
#include <stack>
#include <map>
using namespace std;

template<typename T>
void fun(T &a,T &b)
{
    a = a+b;
    b = a-b;
    a = a-b;
}

int main()
{
    int a = 1;
    int b = 2;
    cout<<a<<" "<<b<<endl;
    fun(a,b);
    cout<<a<<" "<<b<<endl;
    return 0;
}