交换两个数字 [英] swap two numbers

问题描述

大家好，

这一直是一个有趣的话题。你可以使用temp（作为第三个变量）交换两个

数字（比如a和b）。你也可以在不使用第三个变量的情况下交换

。[a = a + b; b = a-b; a = a-b; ]这也是在三个陈述中完成的。任何人都可以建议交换任何东西

少于那个。

hello all,
this has been an interesting topic since long. you can swap two
numbers (say a and b) using temp(as third variable). you can also swap
without using third variable.like[ a=a+b;b=a-b;a=a-b; ]This was also
done in three statements. Can anyon suggest this swapping in anything
less then that.

推荐答案

Abhishek Jha写道：

Abhishek Jha wrote:

这一直是一个有趣的话题。你可以使用temp（作为第三个变量）交换两个
数字（比如a和b）。你也可以交换
而不使用第三个变量。像[a = a + b; b = a-b; a = a-b; ]这也是在三个陈述中完成的。任何人都可以建议交换任何东西
少于那个。

this has been an interesting topic since long. you can swap two
numbers (say a and b) using temp(as third variable). you can also swap
without using third variable.like[ a=a+b;b=a-b;a=a-b; ]This was also
done in three statements. Can anyon suggest this swapping in anything
less then that.

a = a-（b =（a = a + b）-b）;


-

如果每个人都读到USENET会更好：
http://www.expita.com/nomime.html
http://www.netmeister.org/news/learn2quote2.html
http://www.catb.org/~esr/faqs/smart-questions.html

a = a-(b=(a=a+b)-b);

--
USENET would be a better place if everybody read:
http://www.expita.com/nomime.html
http://www.netmeister.org/news/learn2quote2.html
http://www.catb.org/~esr/faqs/smart-questions.html

" Abhishek Jha" < AB *********** @ yahoo.co.in>在消息中写道

news：60 ************************** @ posting.google.c om ...

"Abhishek Jha" <ab***********@yahoo.co.in> wrote in message
news:60**************************@posting.google.c om...

大家好，
这一直是一个有趣的话题。你可以使用temp（作为第三个变量）交换两个
数字（比如a和b）。你也可以交换
而不使用第三个变量。像[a = a + b; b = a-b; a = a-b; ]这也是在三个陈述中完成的。任何人都可以建议交换任何东西
少于那个。

hello all,
this has been an interesting topic since long. you can swap two
numbers (say a and b) using temp(as third variable). you can also swap
without using third variable.like[ a=a+b;b=a-b;a=a-b; ]This was also
done in three statements. Can anyon suggest this swapping in anything
less then that.

[a = a + b; b = a-b; a = a-b;由于可能的
溢出，交换两个数字的方法很糟糕。不使用临时变量的更好方法是使用

XOR技巧[*]（也适用于非整数类型）。但是，最好的方式可能只是使用标准的临时变量，让

编译器进行优化。

[*] a ^ = b; b ^ = A; a ^ = b;

[ a=a+b;b=a-b;a=a-b; ] is a bad way to swap two numbers due to possible
overflow. A better method without using a temporary variable is to use the
XOR trick[*] (which works for non-integral types as well). But, the best
way is probably just to use a standard temporary variable and let the
compiler do the optimization.
[*] a^=b; b^=a; a^=b;

Pedro Graca写道：

Pedro Graca wrote:

Abhishek Jha写道：

Abhishek Jha wrote:

这一直是一个有趣的话题。你可以使用temp（作为第三个变量）交换两个
数字（比如a和b）。你也可以在不使用第三个变量的情况下交换
。[a = a + b; b = a-b; a = a-b; ]这是
也在三个陈述中完成。任何人都可以建议在
之间交换任何东西。

this has been an interesting topic since long. you can swap two
numbers (say a and b) using temp(as third variable). you can also swap without using third variable.like[ a=a+b;b=a-b;a=a-b; ]This was also done in three statements. Can anyon suggest this swapping in anything less then that.

a = a-（b =（a = a + b）-b）;

a = a-(b=(a=a+b)-b);

这比原始的愚蠢更糟糕，因为它总是调用

未定义的行为。


Rob Gamble

This is even worse than the original silliness as it always invokes
undefined behavior.

Rob Gamble

这篇关于交换两个数字的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！