//判断大小端字节序
void judgeEndian()
{
    int num = 0x01020304;
    char* pchar = (char*)#
    if(*pchar==0x01)
    {
        printf("the endian is Big-Endian\n");
    }else if(*pchar==0x04)
    {
        printf("the endian is little-Endian\n");
    }else
    {
        printf("other-Endian\n");
    }
}

//改变数字num的字节序
//如果是大端转化为小端
//如果是小端转化为大端
int changeEndian(int num)
{
    int d = num&0xff;
    num>>=8;
    int c = num&0xff;
    num>>=8;
    int b = num&0xff;
    num>>=8;
    return (d<<24)|(c<<16)|(b<<8)|num;
}

#include <stdio.h>
#include <stdlib.h>
//判断大小端字节序
void judgeEndian()
{
    int num = 0x01020304;
    char* pchar = (char*)&num;
    if(*pchar==0x01)
    {
        printf("the endian is Big-Endian\n");
    }else if(*pchar==0x04)
    {
        printf("the endian is little-Endian\n");
    }else
    {
        printf("other-Endian\n");
    }
}
//改变数字num的字节序
//如果是大端转化为小端
//如果是小端转化为大端
int changeEndian(int num)
{
    char* p = (char*)&num;
    int d = (*p++)&0xff;
    int c = (*p++)&0xff;
    int b = (*p++)&0xff;
    int a = *p;
    return (d<<24)|(c<<16)|(b<<8)|a;
}
int main()
{
    judgeEndian();
    int num = 0x11223344;
    printf("before change endian , num = 0x%x\n",num);
    printf("after  change endian , num = 0x%x\n",changeEndian(num));
    return 0;
}