不使用tmp变量交换两个整数？ [英] swap two integers without using a tmp variable?
问题描述
如何在不使用tmp变量的情况下重写交换函数
交换函数????
int main（）
{
int x = 3;
int y = 5;
//通过引用传递
cout<< 通过引用传递，之前 << endl;
cout<< x = << x<< " y =" << y<< endl;
swap（x，y）;
cout<< 通过引用传递，之后 << endl;
cout<< x = << x<< " y =" << y<< endl;
返回0;
}
void swap（int& x，int& y ）
{
int tmp;
tmp = x;
x = y;
y = tmp;
}
How do you rewrite the swap function without using a tmp variable in
the swap function????
int main()
{
int x = 3;
int y = 5;
// Passing by reference
cout << "Passed by reference, before" << endl;
cout << "x = " << x << " y = " << y << endl;
swap(x,y);
cout << "Passed by reference, after" << endl;
cout << "x = " << x << " y = " << y << endl;
return 0;
}
void swap(int &x, int &y)
{
int tmp;
tmp = x;
x = y;
y = tmp;
}
推荐答案
" Steve" <纳克***** @ my-deja.com>写道...
"Steve" <ng*****@my-deja.com> wrote...
如何在不使用交换函数的tmp变量的情况下重写交换函数????
How do you rewrite the swap function without using a tmp variable in
the swap function????
以前有一个流行的技巧，包括在
三步中对整数进行异或运算，这样你就可以避免定义一个临时的
存储，但它要少得多清楚而不是暂时的。
int a = 42，b = 73;
b = a ^ b;
a = b ^ a;
b = a ^ b;
//这里''''是73，''b''是42.
但是，最好依靠std :: swap来实现。
V
There used to be a popular trick involving XORing the integers in
three steps, which allowed you to avoid having to define a temporary
storage, but it is much less clear than with a temporary.
int a = 42, b = 73;
b = a ^ b;
a = b ^ a;
b = a ^ b;
// here ''a'' is 73, ''b'' is 42.
However, it''s better to rely on std::swap for that.
V
Steve 2004-06-22：
Steve 2004-06-22 :
如何在不使用交换函数的tmp变量的情况下重写交换函数????
How do you rewrite the swap function without using a tmp variable in
the swap function????
通过做一些可以被称为交叉xoring的东西，与运营商^ =
我把它留作练习，因为它很有趣:-)
（不要担心tmp：记住自动变量可以存在于
寄存器中）
Walter Tross
By doing something which could be called cross-xoring, with operator ^=
I leave it as an exercise, since it is fun :-)
(Don''t worry about the tmp: remember that auto variables can live in
registers)
Walter Tross
2004年6月22日星期二00:15:43 GMT，Victor Bazarov< v。******** @ comAcast.net>写道：
On Tue, 22 Jun 2004 00:15:43 GMT, Victor Bazarov <v.********@comAcast.net> wrote:
曾经有过一个流行的技巧，涉及对三个步骤进行整数异或，这样就可以避免定义一个临时的存储，但是它比临时的要清楚得多。
int a = 42，b = 73;
b = a ^ b;
a = b ^ a;
b = a ^ b;
//这里''''是73，''b''是42。
There used to be a popular trick involving XORing the integers in
three steps, which allowed you to avoid having to define a temporary
storage, but it is much less clear than with a temporary.
int a = 42, b = 73;
b = a ^ b;
a = b ^ a;
b = a ^ b;
// here ''a'' is 73, ''b'' is 42.
或者可以使用定期加法和结构：
b = a + b;
a = b - a;
b = b - a;
-
Maxim Yegorushkin
Or one can use regular addition and substruction:
b = a + b;
a = b - a;
b = b - a;
--
Maxim Yegorushkin
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