1.创建临时变量

int main()
{
	int a=10;
	int b=20;
	int tmp=0;
	printf("before:a:%d,b:%d\n",a,b);
    tmp=a;
	a=b;
	b=tmp;
	printf("after :a:%d,b:%d\n",a,b);
	return 0;
}

2.加减法

int main()
{
	int a=10;
	int b=20;
	printf("before:a:%d,b:%d\n",a,b);
    a=a+b;
	b=a-b;
	a=a-b;
	printf("after :a:%d,b:%d\n",a,b);
	return 0;
}

3.异或法

int main()
{
	int a=10;
	int b=20;
	printf("before:a:%d,b:%d\n",a,b);
    a=a^b;
	b=a^b;
	a=a^b;
	printf("after :a:%d,b:%d\n",a,b);
	return 0;
}