B00002 C语言位字段实例

本程序源自维基百科。

Declaring a bit field in C:

#include <stdio.h>

// opaque and show
#define YES 1
#define NO  0

// line styles
#define SOLID  1
#define DOTTED 2
#define DASHED 3

// primary colors
#define BLUE  4  /* 100 */
#define GREEN 2  /* 010 */
#define RED   1  /* 001 */

// mixed colors
#define BLACK   0                    /* 000 */
#define YELLOW  (RED | GREEN)        /* 011 */
#define MAGENTA (RED | BLUE)         /* 101 */
#define CYAN    (GREEN | BLUE)       /* 110 */
#define WHITE   (RED | GREEN | BLUE) /* 111 */

const char * colors[8] = {"Black", "Red", "Green", "Yellow", "Blue", "Magenta", "Cyan", "White"};

// bit field box properties
struct box_props
{
     unsigned int opaque       : 1;
     unsigned int fill_color   : 3;
     unsigned int              : 4; // fill to 8 bits
     unsigned int show_border  : 1;
     unsigned int border_color : 3;
     unsigned int border_style : 2;
     unsigned int              : 0; // fill to nearest byte (16 bits)
     unsigned char width       : 4, // Split a byte into 2 fields of 4 bits
                   height      : 4;
};