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

 1 #include <iostream>
 2 #include <queue>
 3 #include <climits>
 4 #include <algorithm>
 5 #include <memory.h>
 6 #include <stdio.h>
 7 #include <ostream>
 8 #include <vector>
 9 #include <list>
10 #include <cmath>
11 #include <string>
12 #include <stdexcept>
13 #include <stack>
14 #include <map>
15 using namespace std;
16 
17 template<typename T>
18 void fun(T &a,T &b)
19 {
20     a = a+b;
21     b = a-b;
22     a = a-b;
23 }
24 
25 int main()
26 {
27     int a = 1;
28     int b = 2;
29     cout<<a<<" "<<b<<endl;
30     fun(a,b);
31     cout<<a<<" "<<b<<endl;
32     return 0;
33 }