Temp

联合体位域用法

#include <stdio.h>

typedef unsigned char BYTE;

typedef union _BYTE_BITS
{
    BYTE byte;
    struct
    {
        unsigned char bit0:1;
        unsigned char bit1:1;
        unsigned char bit2:1;
        unsigned char bit3:1;
        unsigned char bit4:1;
        unsigned char bit5:1;
        unsigned char bit6:1;
        unsigned char bit7:1;
    } bits;
} BYTE_BITS;

typedef unsigned short WORD;
typedef union _WORD_BYTES
{
    WORD word;
    BYTE bytes[2];
    struct
    {
        BYTE low;
        BYTE high;
    } byte;
    struct
    {
        unsigned char bit0:1;
        unsigned char bit1:1;
        unsigned char bit2:1;
        unsigned char bit3:1;
        unsigned char bit4:1;
        unsigned char bit5:1;
        unsigned char bit6:1;
        unsigned char bit7:1;
        unsigned char bit8:1;
        unsigned char bit9:1;
        unsigned char bit10:1;
        unsigned char bit11:1;
        unsigned char bit12:1;
        unsigned char bit13:1;
        unsigned char bit14:1;
        unsigned char bit15:1;
    } bits;
} WORD_BYTES;

typedef unsigned int DWORD;
typedef union _DWORD_BYTE
{
    DWORD dword;
	WORD words[2];
    BYTE bytes[4];
    struct
    {
        WORD low;
        WORD high;
    } word;
    struct
    {
        BYTE LB;
        BYTE HB;
        BYTE UB;
        BYTE MB;
    } byte;
    struct
    {
        unsigned char bit0:1;
        unsigned char bit1:1;
        unsigned char bit2:1;
        unsigned char bit3:1;
        unsigned char bit4:1;
        unsigned char bit5:1;
        unsigned char bit6:1;
        unsigned char bit7:1;
        unsigned char bit8:1;
        unsigned char bit9:1;
        unsigned char bit10:1;
        unsigned char bit11:1;
        unsigned char bit12:1;
        unsigned char bit13:1;
        unsigned char bit14:1;
        unsigned char bit15:1;
        unsigned char bit16:1;
        unsigned char bit17:1;
        unsigned char bit18:1;
        unsigned char bit19:1;
        unsigned char bit20:1;
        unsigned char bit21:1;
        unsigned char bit22:1;
        unsigned char bit23:1;
        unsigned char bit24:1;
        unsigned char bit25:1;
        unsigned char bit26:1;
        unsigned char bit27:1;
        unsigned char bit28:1;
        unsigned char bit29:1;
        unsigned char bit30:1;
        unsigned char bit31:1;
    } bits;
} DWORD_BYTES;


int main(void) {
	// your code goes here
	DWORD_BYTES word;
	word.bits.bit0 = 1;
	word.bits.bit4 = 1;
	word.bits.bit9 = 1;
	
	printf("0x%.4x\n", word.bits);
	return 0;
}