一、描述：交换两个数字。

二、程序：

方法一：创建临时变量

#include<stdio.h>
#include<windows.h>
int main(){
	int a = 0, b = 0;
	int temp = 0;
	printf("请输入两个数字：");
	scanf_s("%d %d", &a, &b);
	printf("Before:a=%d b=%d\n", a, b);
	temp = a;
	a = b;
	b = temp;
	printf("Atfer :a=%d b=%d\n", a, b);
	system("pause");
	return 0;
}

方法二：迭代法

#include<stdio.h>
#include<windows.h>
int main(){
	int a = 0, b = 0;
	int temp = 0;
	printf("请输入两个数字：");
	scanf_s("%d %d", &a, &b);
	printf("Before:a=%d b=%d\n", a, b);
	a = a + b;
	b = a - b;   //b=a+b-b;
	a = a - b;   //a=a-(a-b);
	printf("Atfer :a=%d b=%d\n", a, b);
	system("pause");
	return 0;
}

方法三：异或运算

#include<stdio.h>
#include<windows.h>
int main(){
	int a = 0, b = 0;
	int temp = 0;
	printf("请输入两个数字：");
	scanf_s("%d %d", &a, &b);
	printf("Before:a=%d b=%d\n", a, b);
	a = a^b;
	b = a^b;//即b=a^b^b(支持结合律，交换律)   b^b为0  a^0--->a 
	a = a^b;//即a=a^a^b.
	printf("Atfer :a=%d b=%d\n", a, b);
	system("pause");
	return 0;
}

注意：一个数和0异或等于该数

三、运行结果：