C语言函数大全--g开头的函数（下）

C语言函数大全

本篇介绍C语言函数大全–g开头的函数（下）

17. getmodename

17.1 函数说明

函数声明	函数功能
char * getmodename(int mode_name);	获取指定的图形模式名

17.2 演示示例

#include 
#include 
#include 

int main(void)
{
    int gdriver = DETECT, gmode, errorcode;
    int midx, midy, mode;
    char numname[80], modename[80];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    midx = getmaxx() / 2;
    midy = getmaxy() / 2;

    mode = getgraphmode();
    sprintf(numname, "%d is the current mode number.", mode);
    sprintf(modename, "%s is the current graphics mode.", getmodename(mode));

    settextjustify(CENTER_TEXT, CENTER_TEXT);
    outtextxy(midx, midy, numname);
    outtextxy(midx, midy+2*textheight("W"), modename);

    getch();
    closegraph();
    return 0;
}

17.3 运行结果

18. getmoderange

18.1 函数说明

函数声明	函数功能
void getmoderange(int graphdriver, int *lomode, int *himode);	获取给定图形驱动程序的模式范围

18.2 演示示例

#include 
#include 
#include 

int main()
{
    int gdriver = DETECT, gmode, errorcode;
    int midx, midy, low, high;
    char mrange[80];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    midx = getmaxx() / 2;
    midy = getmaxy() / 2;

    getmoderange(gdriver, &low, &high);

    sprintf(mrange, "This driver supports modes %d~%d", low, high);

    settextjustify(CENTER_TEXT, CENTER_TEXT);
    outtextxy(midx, midy, mrange);

    getch();
    closegraph();
    return 0;
}

18.3 运行结果

19. getpalette

19.1 函数说明

函数声明	函数功能
void getpalette(struct palettetype *palette);	获取有关当前调色板的信息

19.2 演示示例

#include 
#include 
#include 

int main()
{
    int gdriver = DETECT, gmode, errorcode;
    struct palettetype pal;
    char psize[80], pval[20];
    int i, ht;
    int y = 10;

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    getpalette(&pal);

    sprintf(psize, "The palette has %d modifiable entries.", pal.size);

    outtextxy(0, y, psize);
    if (pal.size != 0)
    {
        ht = textheight("W");
        y += 2*ht;
        outtextxy(0, y, "Here are the current values:");
        y += 2*ht;
        for (i=0; i < pal.size; i++, y+=ht)
        {
            sprintf(pval, "palette[%02d]: 0x%02X", i, pal.colors[i]);
            outtextxy(0, y, pval);
        }
    }

    getch();
    closegraph();
    return 0;
}

19.3 运行结果

20. getpixel

20.1 函数说明

函数声明	函数功能
int getpixel(int x, int y);	获取得指定像素的颜色

20.2 演示示例

#include 
#include 
#include 
#include 

#define PIXEL_COUNT 1000
#define DELAY_TIME  100

int main(void)
{
    int gdriver = DETECT, gmode, errorcode;
    int midx, midy, x, y, color, maxx, maxy, maxcolor;
    char mPixel[50];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    midx = getmaxx() / 2;
    midy = getmaxy() / 2;

    maxx = getmaxx() + 1;
    maxy = getmaxy() + 1;
    maxcolor = getmaxcolor() + 1;

    while (!kbhit())
    {
        srand((unsigned)time(NULL));
        x = rand() % maxx;
        y = rand() % maxy;
        color = rand() % maxcolor;
        putpixel(x, y, color);

        sprintf(mPixel, "color of pixel at (%d,%d) = %d", x, y, getpixel(x, y));
        settextjustify(CENTER_TEXT, CENTER_TEXT);
        outtextxy(midx, midy, mPixel);

        delay(DELAY_TIME);

        cleardevice();
    }

    getch();
    closegraph();
    return 0;
}

20.3 运行结果

21. gets

21.1 函数说明

函数声明	函数功能
	从标准输入流中读取字符串，直至遇到到换行符或EOF时停止，并将读取的结果存放在 buffer 指针所指向的字符数组中。换行符不作为读取串的内容，读取的换行符被转换为 '\0' 空字符，并由此来结束字符串。

注意： gets 函数可以无限读取，易发生溢出。如果溢出，多出来的字符将被写入到堆栈中，这就覆盖了堆栈原先的内容，破坏一个或多个不相关变量的值。

21.2 演示示例

#include 

int main()
{
   char string[80];

   printf("Input a string:");
   gets(string);
   printf("The string input was: %s\n", string);
   return 0;
}

21.3 运行结果

22. gettextsettings

22.1 函数说明

函数声明	函数功能
void gettextsettings(struct textsettingstype *textinfo);	获取有关当前图形文本字体的信息

22.2 演示示例

#include 
#include 
#include 
#include 

// 文本字体
char *font[] = { "DEFAULT_FONT",
                 "TRIPLEX_FONT",
                 "SMALL_FONT",
                 "SANS_SERIF_FONT",
                 "GOTHIC_FONT"
               };

// 文本方向
char *dir[] = { "HORIZ_DIR", "VERT_DIR" };

// 文本水平对齐方式
char *hjust[] = { "LEFT_TEXT", "CENTER_TEXT", "RIGHT_TEXT" };

// 文本垂直对齐方式
char *vjust[] = { "BOTTOM_TEXT", "CENTER_TEXT", "TOP_TEXT" };

int main()
{
    int gdriver = DETECT, gmode, errorcode;
    struct textsettingstype textinfo;
    int midx, midy, ht;
    char fontstr[80], dirstr[80], sizestr[80];
    char hjuststr[80], vjuststr[80];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    midx = getmaxx() / 2;
    midy = getmaxy() / 2;

    // 获取有关当前图形文本字体的信息
    gettextsettings(&textinfo);

    sprintf(fontstr, "%s is the text style.", font[textinfo.font]);
    sprintf(dirstr, "%s is the text direction.", dir[textinfo.direction]);
    sprintf(sizestr, "%d is the text size.", textinfo.charsize);
    sprintf(hjuststr, "%s is the horizontal justification.", hjust[textinfo.horiz]);
    sprintf(vjuststr, "%s is the vertical justification.", vjust[textinfo.vert]);

    ht = textheight("W");
    settextjustify(CENTER_TEXT, CENTER_TEXT);
    outtextxy(midx, midy, fontstr);
    outtextxy(midx, midy+2*ht, dirstr);
    outtextxy(midx, midy+4*ht, sizestr);
    outtextxy(midx, midy+6*ht, hjuststr);
    outtextxy(midx, midy+8*ht, vjuststr);

    getch();
    closegraph();
    return 0;
}

22.3 运行结果

23. getviewsettings

23.1 函数说明

函数声明	函数功能
void getviewsettings(struct viewporttype *viewport);	获取有关当前视区的信息

23.2 演示示例

#include 
#include 
#include 

char *clip[] = { "OFF", "ON" };

int main()
{
    int gdriver = DETECT, gmode, errorcode;
    struct viewporttype viewinfo;
    int midx, midy, ht;
    char topstr[80], botstr[80], clipstr[80];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    midx = getmaxx() / 2;
    midy = getmaxy() / 2;

    // 获取有关当前视区的信息
    getviewsettings(&viewinfo);

    sprintf(topstr, "(%d, %d) is the upper left viewport corner.", viewinfo.left, viewinfo.top);
    sprintf(botstr, "(%d, %d) is the lower right viewport corner.", viewinfo.right, viewinfo.bottom);
    sprintf(clipstr, "Clipping is turned %s.", clip[viewinfo.clip]);

    settextjustify(CENTER_TEXT, CENTER_TEXT);
    ht = textheight("W");
    outtextxy(midx, midy, topstr);
    outtextxy(midx, midy+2*ht, botstr);
    outtextxy(midx, midy+4*ht, clipstr);

    getch();
    closegraph();
    return 0;
}

23.3 运行结果

24. getw

24.1 函数说明

函数声明	函数功能
int getw(FILE *strem);	从 stream 所指向文件读取下一个整数

24.2 演示示例

#include 
#include 

#define FNAME "test.txt"

int main(void)
{
    FILE *fp;
    int word;

    fp = fopen(FNAME, "wb");
    if (fp == NULL)
    {
        printf("Error opening file %s\n", FNAME);
        exit(1);
    }

    word = 94;
    putw(word,fp);
    if (ferror(fp))
        printf("Error writing to file\n");
    else
        printf("Successful write\n");
    fclose(fp);

    fp = fopen(FNAME, "rb");
    if (fp == NULL)
    {
        printf("Error opening file %s\n", FNAME);
        exit(1);
    }

    word = getw(fp);
    if (ferror(fp))
        printf("Error reading file\n");
    else
        printf("Successful read: word = %d\n", word);

    fclose(fp);
    unlink(FNAME);

    return 0;
}

24.3 运行结果

25. getx，gety

25.1 函数说明

函数声明	函数功能
int getx(void);	获取当前图形位置的 x 坐标
	获取当前图形位置的 y 坐标

25.2 演示示例

#include 
#include 
#include 

int main(void)
{
    int gdriver = DETECT, gmode, errorcode;
    char msg[80];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    moveto(getmaxx() / 2, getmaxy() / 2);

    sprintf(msg, "<-(%d, %d) is the here.", getx(), gety());

    outtext(msg);

    getch();
    closegraph();
    return 0;
}

25.3 运行结果

26. gmtime

26.1 函数说明

函数声明	函数功能
struct tm *gmtime(long *clock);	把日期和时间转换为格林尼治标准时间(GMT)

26.2 演示示例

#include 
#include 
#include 
#include 

// 太平洋标准时间和夏令时
char *tzstr = "TZ=PST8PDT";

int main(void)
{
    time_t t;
    struct tm *gmt, *area;
    putenv(tzstr); // 用来改变或增加环境变量的内容
    tzset(); // UNIX时间兼容函数
    // 获取当前的系统时间，其值表示从协调世界时（Coordinated Universal Time）
    // 1970年1月1日00:00:00（称为UNIX系统的Epoch时间）到当前时刻的秒数。
    t = time(NULL); 
    area = localtime(&t); // 把从1970-1-1零点零分到当前时间系统所偏移的秒数时间转换为本地时间
    // asctime 把timeptr指向的tm结构体中储存的时间转换为字符串
    printf("Local time is: %s", asctime(area));
    // 把日期和时间转换为格林尼治标准时间(GMT)
    gmt = gmtime(&t);
    printf("GMT is:        %s", asctime(gmt));
    return 0;
}

26.3 运行结果

27. graphdefaults

27.1 函数说明

函数声明	函数功能
void graphdefaults(void);	将所有图形设置复位为它们的缺省值

27.2 演示示例

#include 
#include 
#include 
#include 

int main(void)
{
    int gdriver = DETECT, gmode, errorcode;
    int maxx, maxy;

    initgraph(&gdriver, &gmode, "c:\\bor\\Borland\\bgi");
    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    maxx = getmaxx();
    maxy = getmaxy();

    setlinestyle(DOTTED_LINE, 0, 3);
    line(0, 0, maxx, maxy);
    outtextxy(maxx/2, maxy/3, "Before default values are restored.");
    getch();

    // 将所有图形设置复位为它们的缺省值
    graphdefaults();

    cleardevice();

    line(0, 0, maxx, maxy);
    outtextxy(maxx/2, maxy/3, "After restoring default values.");

    getch();
    closegraph();
    return 0;
}

27.3 运行结果

28. grapherrormsg

28.1 函数说明

函数声明	函数功能
char * grapherrormsg(int errorcode);	返回一个错误信息串的指针

28.2 演示示例

#include 
#include 
#include 

#define NONSENSE -50

int main(void)
{
    // FORCE AN ERROR TO OCCUR
    int gdriver = NONSENSE, gmode, errorcode;

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();

    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    line(0, 0, getmaxx(), getmaxy());

    getch();
    closegraph();
    return 0;
}

28.3 运行结果

29. graphresult

29.1 函数说明

函数声明	函数功能
int graphresult(void);	返回最后一次不成功的图形操作的错误代码

29.2 演示示例

#include 
#include 
#include 
#include 

int main(void)
{
    // request auto detection
    int gdriver = DETECT, gmode, errorcode;

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    line(0, 0, getmaxx(), getmaxy());

    getch();
    closegraph();
    return 0;
}

29.3 运行结果

30. getmaxwidth，getmaxheight

30.1 函数说明

函数声明	函数功能
int getmaxwidth(void);	获取屏幕的最大宽度
int getmaxheight(void);	获取屏幕的最大高度

30.2 演示示例

#include 
#include 
#include 

int main()
{
    int gdriver = DETECT, gmode, errorcode;
    int midx, midy;
    char ch[80];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    midx = getmaxx() / 2;
    midy = getmaxy() / 2;

    sprintf(ch, "maxwidth = %d, maxheight = %d", getmaxwidth(), getmaxheight());

    settextjustify(CENTER_TEXT, CENTER_TEXT);
    outtextxy(midx, midy, ch);

    getch();
    closegraph();
    return 0;
}

30.3 运行结果

31. getdisplaycolor

31.1 函数说明

函数声明	函数功能
int getdisplaycolor( int color );	根据 color ，返回要显示的颜色值

注意： color = -1 , 则返回 WHITE = 15 的颜色值；color < - 1 或 color > 15，则输出一个8位整数。

31.2 演示示例

#include 
#include 
#include 

int main()
{
    int gdriver = DETECT, gmode, errorcode;
    int midx, midy;
    char ch[80];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    midx = getmaxx() / 2;
    midy = getmaxy() / 2;

    sprintf(ch, "color = %d, displaycolor(-1) = %d, displaycolor(16) = %d", getcolor(), getdisplaycolor(-1), getdisplaycolor(16));

    settextjustify(CENTER_TEXT, CENTER_TEXT);
    outtextxy(midx, midy, ch);

    getch();
    closegraph();
    return 0;
}

31.3 运行结果

32. getwindowwidth，getwindowheight

32.1 函数说明

函数声明	函数功能
int getwindowwidth();	获取图形界面窗口宽度
int getwindowheight(void);	获取图形界面窗口高度

32.2 演示示例

#include 
#include 
#include 

int main()
{
    int gdriver = DETECT, gmode, errorcode;
    int midx, midy, low, high;
    char ch[80];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    midx = getmaxx() / 2;
    midy = getmaxy() / 2;

    sprintf(ch, "windowwidth = %d, windowheight = %d", getwindowwidth(), getwindowheight());

    settextjustify(CENTER_TEXT, CENTER_TEXT);
    outtextxy(midx, midy, ch);

    getch();
    closegraph();
    return 0;
}

32.3 运行结果

33. getrefreshingbgi

33.1 函数说明

函数声明	函数功能
bool getrefreshingbgi(void);	获取刷新基础图形界面标识

33.2 演示示例

#include 
#include 
#include 

int main()
{
    int gdriver = DETECT, gmode, errorcode;
    int midx, midy, low, high;
    char ch[80];

    initgraph(&gdriver, &gmode, "");

    errorcode = graphresult();
    if (errorcode != grOk)
    {
        printf("Graphics error: %s\n", grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }

    midx = getmaxx() / 2;
    midy = getmaxy() / 2;

    sprintf(ch, "refreshingbgi = %d", getrefreshingbgi());

    settextjustify(CENTER_TEXT, CENTER_TEXT);
    outtextxy(midx, midy, ch);

    getch();
    closegraph();
    return 0;
}

33.3 运行结果

参考

1. [API Reference Document]
2. [gets]