引入第三个变量
int t = a;
a = b;
b = t;
算术运算
a = b-a;//求出a,b在数轴上的距离
b = b-a;//b到原点的距离与ab间距离之差
a = b+a;//b到原点的距离加上ab距离即为a到原点距离
异或运算
a = a^b;
b = a^b;
a = a^b;
int t = a;
a = b;
b = t;
a = b-a;//求出a,b在数轴上的距离
b = b-a;//b到原点的距离与ab间距离之差
a = b+a;//b到原点的距离加上ab距离即为a到原点距离
a = a^b;
b = a^b;
a = a^b;