g函数.txt

C语言函数..应用示例

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;
}
 
 

函数名: gety
功  能: 返回当前图形位置的y坐标
用  法: int far gety(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;
}
 
 

函数名: gmtime
功  能: 把日期和时间转换为格林尼治标准时间(GMT)
用  法: struct tm *gmtime(long *clock);
程序例:

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

/* Pacific Standard Time & Daylight Savings */
char *tzstr = "TZ=PST8PDT";

int main(void)
{
   time_t t;
   struct tm *gmt, *area;

   putenv(tzstr);
   tzset();

   t = time(NULL);
   area = localtime(&t);
   printf("Local time is: %s", asctime(area));
   gmt = gmtime(&t);
   printf("GMT is:        %s", asctime(gmt));
   return 0;
}
 
 

函数名: gotoxy
功  能: 在文本窗口中设置光标
用  法: void gotoxy(int x, int y);
程序例:

#include <conio.h>

int main(void)
{
   clrscr();
   gotoxy(35, 12);
   cprintf("Hello world");
   getch();
   return 0;
}
 
 

函数名: gotoxy
功  能: 在文本窗口中设置光标
用  法: void gotoxy(int x, int y);
程序例:

#include <conio.h>

int main(void)
{
   clrscr();
   gotoxy(35, 12);
   cprintf("Hello world");
   getch();
   return 0;
}
 
 

函数名: graphdefaults
功  能: 将所有图形设置复位为它们的缺省值
用  法: void far graphdefaults(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;
   int maxx, maxy;

   /* initialize graphics and local variables */
   initgraph(&gdriver, &gmode, "c:\\bor\\Borland\\bgi");

   /* 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 */
   }

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

   /* output line with non-default settings */
   setlinestyle(DOTTED_LINE, 0, 3);
   line(0, 0, maxx, maxy);
   outtextxy(maxx/2, maxy/3, "Before default values are restored.");
   getch();

   /* restore default values for everything */
   graphdefaults();

   /* clear the screen */
   cleardevice();

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

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

函数名: grapherrormsg
功  能: 返回一个错误信息串的指针
用  法: char *far grapherrormsg(int errorcode);
程序例:

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

#define NONSENSE -50

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

   /* initialize graphics mode */
   initgraph(&gdriver, &gmode, "");

   /* read result of initialization */
   errorcode = graphresult();

   /* if an error occurred, then output a */
   /* descriptive error message.          */
   if (errorcode != grOk)
   {
      printf("Graphics error: %s\n", grapherrormsg(errorcode));
      printf("Press any key to halt:");
      getch();
      exit(1); /* terminate with an error code */
   }

   /* draw a line */
   line(0, 0, getmaxx(), getmaxy());

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

函数名: graphresult
功  能: 返回最后一次不成功的图形操作的错误代码
用  法: int far graphresult(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;

   /* 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 */
   }

   /* draw a line */
   line(0, 0, getmaxx(), getmaxy());

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

函数名: _graphfreemem
功  能: 用户可修改的图形存储区释放函数
用  法: void far _graphfreemem(void far *ptr, unsigned size);
程序例:

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

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

       /* clear the text screen */
       clrscr();
       printf("Press any key to initialize graphics mode:");
       getch();
       clrscr();

       /* 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;

       /* display a message */
       settextjustify(CENTER_TEXT, CENTER_TEXT);
       outtextxy(midx, midy, "Press any key to exit graphics mode:");

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

/* called by the graphics kernel to allocate memory */
void far * far _graphgetmem(unsigned size)
{
       printf("_graphgetmem called to allocate %d bytes.\n", size);
       printf("hit any key:");
       getch();
       printf("\n");

       /* allocate memory from far heap */
       return farmalloc(size);
}

/* called by the graphics kernel to free memory */
void far _graphfreemem(void far *ptr, unsigned size)
{
       printf("_graphfreemem called to free %d bytes.\n", size);
       printf("hit any key:");
       getch();
       printf("\n");

      /* free ptr from far heap */
      farfree(ptr);
}
 

函数名: _graphgetmem
功  能: 用户可修改的图形存储区分配函数
用  法: void far *far _graphgetmem(unsigned size);
程序例:

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

int main(void)
{
   /* request autodetection */
   int gdriver = DETECT, gmode, errorcode;
   int midx, midy;

   /* clear the text screen */
   clrscr();
   printf("Press any key to initialize graphics mode:");
   getch();
   clrscr();

   /* 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;

   /* display a message */
   settextjustify(CENTER_TEXT, CENTER_TEXT);
   outtextxy(midx, midy, "Press any key to exit graphics mode:");

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

/* called by the graphics kernel to allocate memory */
void far * far _graphgetmem(unsigned size)
{
   printf("_graphgetmem called to allocate %d bytes.\n", size);
   printf("hit any key:");
   getch();
   printf("\n");

   /* allocate memory from far heap */
   return farmalloc(size);
}

/* called by the graphics kernel to free memory */
void far _graphfreemem(void far *ptr, unsigned size)
{
   printf("_graphfreemem called to free %d bytes.\n", size);
   printf("hit any key:");
   getch();
   printf("\n");

   /* free ptr from far heap */
   farfree(ptr);
}