c primer plus----第15章 位操作

#include <stdio.h>



#define YES 1

#define NO  0



#define SOLID  0

#define DOTTED 1 //有点的

#define DASHED 2 //虚线



#define BULE   4

#define GREEN  2

#define RED    1



#define BLACK  0

#define YELLOW (RED | GREEN)

#define MAGENTA (RED | BULE)

#define CYAN (GREEN | BLUE)

#define WHITE (RED | GREEN | BULE)



#define OPAQUE 0x1

#define FILL_BLUE 0x8

//#define FILL_BLUE 1<<3

#define FILL_GREEN 0x4

//#define FILL_GREEN 1<<2



#define FILL_RED 0x2

#define FILL_MASK 0xE

#define BORDER 0x100

#define BORDER_BLUE 0x800

//#define BORDER_BLUE 1<<11

#define BORDER_GREEN 0x400

#define BORDER_RED 0x200

//define BORDER_RED 0010 0000 0000

#define BORDER_MASK 0xE00

#define B_SOLID 0

#define B_DOTTED 0x1000

//#define B_DOTTED 0001 0000 0000 0000

#define B_DASHED 0x2000

#define STYLE_MASK 0x3000

//#define STYLE_MASK 0011 0000 0000 0000



const char * colors[8] = { "black", "red", "green", "yellow", "blue", "magenta",

        "cyan", "white" };



struct box_props {

    unsigned int opaque       : 1;//1

    unsigned int fill_color   : 3;//011

    unsigned int              : 4;//0000

    unsigned int show_border  : 1;//1

    unsigned int border_color : 3;//010

    unsigned int border_style : 2;//010

    unsigned int              : 2;//00

    //               00010010100000111

    //00000000000000000010010100000111

};



union Views

{

    struct box_props st_view;

    unsigned int ui_view;

};



void show_settings(const struct box_props * pb);

void show_settings1(unsigned short us);

char * itobs(int n, char * ps);



//0-9对应0-9;A-F对应10-15

//0 1 2 3 4 5 6 7 8 9 A B C D E F



int main(void)

{

    union Views box = {YES, YELLOW, YES, GREEN, DASHED};

    char bin_str[8 * sizeof(unsigned int) + 1];



    printf("Original box settings:\n");

    show_settings(&box.st_view);



    printf("\nBox settings using unsigned int view:\n");

    show_settings1(box.ui_view);



    //00000000000000000010010100000111

printf("bits are %s\n", itobs(box.ui_view, bin_str));



    box.ui_view &= ~FILL_MASK; //把代表填充颜色的位清0  //~1110  0001

    ////00000000000000000010010100000001

printf("bits are %s\n", itobs(box.ui_view, bin_str));



    box.ui_view |= (FILL_BLUE | FILL_GREEN);//重置填充色 1000 | 100 = 1100

    //00000000000000000010010100001101

printf("bits are %s\n", itobs(box.ui_view, bin_str));

    box.ui_view ^= OPAQUE;//转置指示是否透明的位

    //00000000000000000010010100001101

    //00000000000000000000000000000001



    //00000000000000000010010100001100



printf("bits are %s\n", itobs(box.ui_view, bin_str));

    box.ui_view |= BORDER_RED;//错误的方法

    //00000000000000000000001000000000

    //00000000000000000010011100001100

    box.ui_view &= ~STYLE_MASK;//清除样式位

    //00000000000000000011000000000000



    //11111111111111111100111111111111

    //00000000000000000010011100001100

    //00000000000000000000011100001100



printf("bits are %s\n", itobs(box.ui_view, bin_str));



    box.ui_view |= B_DOTTED;//把样式设置为点

    //00000000000000000000011100001100

    //00000000000000000001000000000000



    //00000000000000000001011100001100



    printf("\nModified box settings:\n");

    show_settings(&box.st_view);



    printf("\nBox settings using unsigned int view:\n");

    show_settings1(box.ui_view);

    printf("bits are %s\n", itobs(box.ui_view, bin_str));



    return 0;

}



char * itobs(int n, char * ps)

{

    int i;

    static int size = 8 * sizeof(unsigned int);

    for (i = size - 1; i >= 0; i--, n >>= 1) //31 --->0

        ps[i] = (01 & n) + '0';



    ps[size] = '\0';



    return ps;

}



void show_settings1(unsigned short us)

{

    //00000000000000000010010100000111

    //                            111

    printf("Box is %s.\n", us & OPAQUE == OPAQUE ? "opaque" : "transparent");

    printf("The fill color is %s.\n", colors[(us >> 1) & 07]);



    printf("Border %s.\n", us & BORDER == BORDER ? "shown" : "not shown");

    printf("The border style is ");

    switch (us & STYLE_MASK) {

        case B_SOLID:

            printf("solid.\n");

            break;

        case B_DOTTED:

            printf("dotted.\n");

            break;

        case B_DASHED:

            printf("dashed.\n");

            break;

        default:

            printf("unknow type.\n");

        break;

    }



    printf("The border color is %s.\n",colors[(us >> 9) & 07]);

}





void show_settings(const struct box_props * pb)

{

    printf("Box is %s.\n", pb->opaque == YES ? "opaque" : "transparent");

    printf("The fill color is %s.\n", colors[pb->fill_color]);

    printf("Border %s.\n", pb->show_border == YES ? "shown" : "not shown");

    printf("The border color is %s.\n", colors[pb->border_color]);

    printf("The border style is ");



    switch (pb->border_style) {

    case SOLID:

        printf("solid.\n");

        break;

    case DOTTED:

        printf("dotted.\n");

        break;

    case DASHED:

        printf("dashed.\n");

        break;

    default:

        printf("unknow type.\n");

        break;

    }

}