C中四种交换数值的方法

#define SWAP1(a, b) \
{                   \
    int temp = a;   \
    a = b;          \
    b = temp;       \
}

#define SWAP2(a, b) \
{                   \
    a = a + b;      \
    b = a - b;      \
    a = a - b;      \
}   //可能会出现溢出

#define SWAP3(a, b) \
{                   \
    a = a ^ b;      \
    b = a ^ b;      \
    a = a ^ b;      \
}

void Swap4(int* a, int* b)  
{
    int c = *a;
    *a = *b;
    *b = c;
}

宏定义的方式在C++中也可用。