变量转换（不使用中间变量）

第一种方法：

a=a+b;

b=a-b;

a=a-b;

 

代码如下：

 

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1. #include "stdio.h"  
2. int main(void)  
3. {  
4.     int a,b;  
5.     printf("请输入两个变量a和b：/n");  
6.     scanf("%d %d",&a,&b);  
7.     printf("a和b交换前：/n");  
8.     printf("a=%d b=%d/n",a,b);  
9.     a=a+b;  
10.     b=a-b;  
11.     a=a-b;  
12.     printf("a和b交换后：/n");  
13.     printf("a=%d b=%d/n",a,b);  
14.     system("pause");  
15.     return 0;  
16. }  

缺点：可能越界

第二种方法：

解决方法：（a、b异或的结果 ，和a异或得b ，和b异或得a）

a=a^b；

b=a^b；

a=a^b；

代码如下：

[cpp:showcolumns] view plaincopy

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1. #include "stdio.h"  
2. int main(void)  
3. {  
4.     int a,b;  
5.     printf("请输入两个变量a和b：/n");  
6.     scanf("%d %d",&a,&b);  
7.     printf("a和b交换前：/n");  
8.     printf("a=%d b=%d/n",a,b);  
9.     a=a^b;  
10.     b=a^b;  
11.     a=a^b;  
12.     printf("a和b交换后：/n");  
13.     printf("a=%d b=%d/n",a,b);  
14.     system("pause");  
15.     return 0;  
16. }  

写成宏替换的方法如下：

[cpp:showcolumns] view plaincopy

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1. #include "stdio.h"  
2. #define swap(a,b) (a)^=(b)^=(a)^=(b)  
3. int main(void)  
4. {  
5.     int a,b;  
6.     printf("请输入两个变量a和b：/n");  
7.     scanf("%d %d",&a,&b);  
8.     printf("a和b交换前：/n");  
9.     printf("a=%d b=%d/n",a,b);  
10.     swap(a,b);  
11.     printf("a和b交换后：/n");  
12.     printf("a=%d b=%d/n",a,b);  
13.     system("pause");  
14.     return 0;  
15. }