什么是大小端

小端存储：The low-order bits of the address store the low-order bits of the data.
大端存储：地址低位存数据高位.

方法一

使用C语言union来判断

#include <stdio.h>

union AA{
    
    char a;
    int b;
};
int main(int argc,const char * argv[])
{
    
    union AA n;
    n.b=0x12345678;
    if(n.a==0x78)
    {
    
        printf("小端存储\n");//小端存储：The low-order bits of the address store the low-order bits of the data
    }
    else if(n.a==0x12)
    {
    
        printf("大端存储\n");//大端存储：地址低位存数据高位
    }
    return 0;
}

方法二

Use pointer coercion

#include <stdio.h>

int main(int argc,const char * argv[])
{
    
    int a=0x12345678;
    char *b=(char *)&a;
    if(*b==0x78)
    {
    
        printf("小端存储\n");
    }
    else if(*b==0x12)
    {
    
        printf("大端存储\n");
    }
}

The above are some simple methods for judging big and small endian storage.