C语言库函数(G类字母)

　　函数名: getpass
功能: 读一个口令
用法: char *getpass(char *prompt);
程序例:

#include <conio.h>

int main(void)
{
char *passWord;

password = getpass("Input a password:");
cprintf("The password is: %s\r\n",
password);
return 0;
}

函数名: getpixel
功能: 取得指定像素的颜色
用法: int far getpixel(int x, int y);
程序例:

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <dos.h>

#define PIXEL_COUNT 1000
#define DELAY_TIME 100 /* in milliseconds */

int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int i, x, y, color, maxx, maxy,
maxcolor, seed;

/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");

/* read result of initialization */
errorcode = graphresult();
/* an error occurred */
if (errorcode != grOk)
{
printf("Graphics error: %s\n",
grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
/* terminate with an error code */
exit(1);
}

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

while (!kbhit())
{
/* seed the random number generator */
seed = random(32767);
srand(seed);
for (i=0; i<PIXEL_COUNT; i++)
{
x = random(maxx);
y = random(maxy);
color = random(maxcolor);
putpixel(x, y, color);
}

delay(DELAY_TIME);
srand(seed);
for (i=0; i<PIXEL_COUNT; i++)
{
x = random(maxx);
y = random(maxy);
color = random(maxcolor);
if (color == getpixel匇? ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;h;(;);;; ;e;t;p;s;p;(;););;; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;e;s;e;t; ;t;o; ;s;e;g;m;e;n;t; ;o;f; ;t;h;e; ;P;S;P; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;i;n;e; ;i;s; ;l;o;c;a;t;e;d; ;a;t; ;o;f;f;s;e;t; ;0;x;8;1; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;t; ;o;f; ;P;S;P; ; ; ; ; ; ; ; ;

函数名: gets
功能: 从流中取一字符串
用法: char *gets(char *string);
程序例:

#include <stdio.h>

int main(void)
{
char string[80];

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

函数名: gettext
功能: 将文本方式屏幕上的文本拷贝到存储区
用法: int gettext(int left, int top, int right, int bottom, void *destin);
程序例:

#include <conio.h>

char buffer[4096];

int main(void)
{
int i;
clrscr();
for (i = 0; i <= 20; i++)
cprintf("Line #%d\r\n", i);
gettext(1, 1, 80, 25, buffer);
gotoxy(1, 25);
cprintf("Press any key to clear screen...");
getch();
clrscr();
gotoxy(1, 25);
cprintf("Press any key to restore screen...");
getch();
puttext(1, 1, 80, 25, buffer);
gotoxy(1, 25);
cprintf("Press any key to quit...");
getch();
return 0;
}

函数名: gettextinfo
功能: 取得文本模式的显示信息
用法: void gettextinfo(strUCt text_info *inforec);
程序例:

#include <conio.h>

int main(void)
{
struct text_info ti;
gettextinfo(&ti);
cprintf("window left %2d\r\n",ti.winleft);
cprintf("window top %2d\r\n",ti.wintop);
cprintf("window right %2d\r\n",ti.winright);
cprintf("window bottom %2d\r\n",ti.winbottom);
cprintf("attribute %2d\r\n",ti.attribute);
cprintf("normal attribute %2d\r\n",ti.normattr);
cprintf("current mode %2d\r\n",ti.currmode);
cprintf("screen height %2d\r\n",ti.screenheight);
cprintf("screen width %2d\r\n",ti.screenwidth);
cprintf("current x %2d\r\n",ti.curx);
cprintf("current y %2d\r\n",ti.cury);
return 0;
}

函数名: gettextsettings
功能: 返回有关当前图形文本字体的信息
用法: void far gettextsettings(struct textsettingstype far *textinfo);
程序例:

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

/* the names of the fonts supported */
char *font[] = { "DEFAULT_FONT",
"TRIPLEX_FONT",
"SMALL_FONT",
"SANS_SERIF_FONT",
"GOTHIC_FONT"
};

/* the names of the text directions supported */
char *dir[] = { "HORIZ_DIR", "VERT_DIR" };

/* horizontal text justifications supported */
char *hjust[] = { "LEFT_TEXT", "CENTER_TEXT", "RIGHT_TEXT" };

/* vertical text justifications supported */
char *vjust[] = { "BOTTOM_TEXT", "CENTER_TEXT", "TOP_TEXT" };

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

/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");

/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}

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

/* get information about current text settings */
gettextsettings(&textinfo);

/* convert text information into strings */
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]);

/* display the information */
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);

/* clean up */
getch();
closegraph();
return 0;
}

函数名: gettime
功能: 取得系统时间
用法: void gettime(struct time *timep);
程序例:

#include <stdio.h>
#include <dos.h>

int main(void)
{
struct time t;

gettime(&t);
printf("The current time is: %2d:%02d:%02d.%02d\n",
t.ti_hour, t.ti_min, t.ti_sec, t.ti_hund);
return 0;
}

函数名: getvect
功能: 取得中断向量入口
用法: void interrupt(*getvect(int intr_num));
程序例:

#include <stdio.h>
#include <dos.h>

void interrupt get_out(); /* interrupt prototype */

void interrupt (*oldfunc)(); /* interrupt function pointer */
int looping = 1;

int main(void)
{
puts("Press <Shift><Prt Sc> to terminate");

/* save the old interrupt */
oldfunc = getvect(5);

/* install interrupt handler */
setvect(5,get_out);

/* do nothing */
while (looping);

/* restore to original interrupt routine */
setvect(5,oldfunc);

puts("Success");
return 0;
}
void interrupt get_out()
{
looping = 0; /* change global variable to get out of loop */
}

函数名: getverify
功能: 返回DOS校验标志状态
用法: int getverify(void);
程序例:

#include <stdio.h>
#include <dos.h>

int main(void)
{
if (getverify())
printf("DOS verify flag is on\n");
else
printf("DOS verify flag is off\n");
return 0;
}

函数名: getviewsetting
功能: 返回有关当前视区的信息
用法: void far getviewsettings(struct viewporttype far *viewport);
程序例:

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

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

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

/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");

/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}

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

/* get information about current viewport */
getviewsettings(&viewinfo);

/* convert text information into strings */
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]);

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

/* clean up */
getch();
closegraph();
return 0;
}

函数名: getw
功能: 从流中取一整数
用法: int getw(FILE *strem);
程序例:

#include <stdio.h>
#include <stdlib.h>

#define FNAME "test.$$$"

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

/* place the word in a file */
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);

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

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

/* clean up */
fclose(fp);
unlink(FNAME);

return 0;
}

函数名: getx
功能: 返回当前图形位置的x坐标
用法: int far getx(void);
程序例:

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
char msg[80];

/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");

/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}

/* move to the screen center point */
moveto(getmaxx() / 2, getmaxy() / 2);

/* create a message string */
sprintf(msg, "<-(%d, %d) is the here.", getx(), gety());

/* display the message */
outtext(msg);

/* clean up */
getch();
closegraph();
return 0;
}