大端法与小端法互换

以int类型为例:

{
    unsigned char *p=rhs;
    unsigned char temp;
    temp=p[0];
    p[0]=[1];
    p[1]=temp;

    temp=p[1];
    p[1]=[2];
    p[2]=temp;
    return ;
}

void swap2(int *rhs)
{
    *rhs=(((*rhs)&0xff000000)>>24) | (((*rhs)&0x00ff0000)>>8) | (((*rhs)&0x000000ff)<<24) | (((*rhs)&0x0000ff00)<<8);
}

    


    int check1()//检查主机字节顺序是否是大端法，如果是，返回1，否则返回0.
    {
        int i=0x12345678;
        unsigned char *p=&i;
        return (0x12==p[0]);
    }

    int check2()
    {
        union{
            unsigned int i;
            unsigned char s[4];
        }c;
        c.i=0x12345678;
        return (0x12==c.s[0]);
    }