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不用第三个变量, 交换两变量的值 (C++)

kitt posted @ 2014年2月28日 17:22 in 技术类 Tech , 1592 阅读

解法还挺多的, 这里有3种。

1. 使用异或(XOR), a ^ a = 0

int a = 3, b = 7;
a = a ^ b;   // a = 3 ^ 7
b = a ^ b;   // b = 3 ^ 7 ^ 7 = 3
a = a ^ b;   // a = 3 ^ 7 ^ 3 = 7

 

2. 求和, 感谢elliot提供这种解法。

int a = 3, b = 7;
a = a + b;   // a = 10
b = a - b;   // b = 3
a = a - b;   // a = 7

 

3. 求差

int a = 3, b = 7;
a = b - a;   // a = 4
b = b - a;   // b = 3
a = b + a;   // a = 7
Avatar_small
elliot 说:
2014年3月04日 07:45

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

Avatar_small
xy 说:
2014年3月10日 12:00

@kitt:
我是晓阳~~
这个是我当时BF的面试题,回来跟我说,我也是想到的是a=a+b, b=a-b,a=a-b
你这个我还没想到,我发给他看看哈哈

Avatar_small
kitt 说:
2014年3月10日 13:15

回复能看到吗? @xy:

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uulm 说:
2014年3月18日 10:42

void swap( int &r,int &s )
{
if( r < s )
{
--s;
swap( r,s );
++r;
}
else if( r > s )
{
--r;
swap( r,s );
++s;
}
}

Avatar_small
uulm 说:
2014年3月18日 10:46

void swap( int &r,int &s )
{
throw r;
catch (int what )
{
r = s;
s = what;
}
}

Avatar_small
elliot 说:
2014年3月24日 02:54

@kitt: 我向来只知道这一种解法...倒是要感谢你让我见识了更多的方法。

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AP 10th Science Ques 说:
2022年9月16日 13:08

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