使用C语言中的联合体

使用联合体将长整型数据的高字节和低字节拆分并输出结果

#include <iostream>

union MyUnion
{
	long _long;
	char _ch[4];
};

int main()
{
	MyUnion unio;
	unio._long = 2147483646;


	for (int i = 0; i < 4; i++)
	{
		printf("%d\n", unio._ch[i]);
	}

	while (true)
	{

	}

	return 0;
}

这是把一个long型用联合体转为char型输出，望采纳！

#include <stdio.h>

typedef union
{
    long num;

    struct
    {
        int low; 
        int high;
    };
}NUM;
                                                                                                                                                                                    
int check_sys()
{
    union _test
    {
        int  a;
        char b;
    } test;

    test.a = 1;

    if (test.b == 1)
    {
        printf("Little_endian!\n");
        return 0;
    }
    else
    {
        printf("Big_endian!\n");
        return 1;
    }
}


int main()
{
    check_sys();

    printf("long size:%lu int size:%lu\n", sizeof(long), sizeof(int));

    NUM test; 
    test.num = 0x2222222211111111;

    printf("high addr:0x%X %X\n", (int)&test.high, test.high);
    printf("low addr:0x%X %X\n", (int)&test.low, test.low);
}

编译输出：

root# gcc 1.c
root# ./a.out 
Little_endian!
long size:8 int size:4
high addr:0x72B612F4 22222222
low addr:0x72B612F0 11111111