c语言库函数大全之一（b开头）

函数名: bar

功  能: 画一个二维条形图

用  法: void far bar(int left, int top, int right, int bottom);

程序例:

#include

#include

#include

#include

int main(void)

{

   /* request auto detection */

   int gdriver = DETECT, gmode, errorcode;

   int midx, midy, i;

   /* 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;

   /* loop through the fill patterns */

   for (i=SOLID_FILL; i

   {

      /* set the fill style */

      setfillstyle(i, getmaxcolor());

      /* draw the bar */

      bar(midx-50, midy-50, midx+50,

         midy+50);

      getch();

   }

   /* clean up */

   closegraph();

   return 0;

}

函数名: bar3d

功  能: 画一个三维条形图

用  法: void far bar3d(int left, int top, int right, int bottom,

                       int depth, int topflag);

程序例:

#include

#include

#include

#include

int main(void)

{   /* request auto detection */

   int gdriver = DETECT, gmode, errorcode;

   int midx, midy, i;

   /* initialize graphics, 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 error code */

   }

   midx = getmaxx() / 2;

   midy = getmaxy() / 2;

   /* loop through the fill patterns */

   for (i=EMPTY_FILL; i

   {

      /* set the fill style */

      setfillstyle(i, getmaxcolor());

      /* draw the 3-d bar */

      bar3d(midx-50, midy-50, midx+50, midy+50, 10, 1);

      getch();

   }

   /* clean up */

   closegraph();

   return 0;

}

函数名: bdos

功  能: DOS系统调用

用  法: int bdos(int dosfun, unsigned dosdx, unsigned dosal);

程序例:

#include

#include

/* Get current drive as 'A', 'B', ... */

char current_drive(void)

{

   char curdrive;

   /* Get current disk as 0, 1, ... */

   curdrive = bdos(0x19, 0, 0);

   return('A' + curdrive);

}

int main(void)

{

   printf("The current drive is %c:\n", current_drive());

   return 0;

}

函数名: bdosptr

功  能: DOS系统调用

用  法: int bdosptr(int dosfun, void *argument, unsigned dosal);

程序例:

#include

#include

#include

#include

#include

#include

#define  BUFLEN  80

int main(void)

{

   char  buffer[BUFLEN];

   int   test;

   printf("Enter full pathname of a directory\n");

   gets(buffer);

   test = bdosptr(0x3B,buffer,0);

      if(test)

      {

  printf("DOS error message: %d\n", errno);

  /* See errno.h for error listings */

  exit (1);

      }

   getcwd(buffer, BUFLEN);

   printf("The current directory is: %s\n", buffer);

   return 0;

}

函数名: bioscom

功  能: 串行I/O通信

用  法: int bioscom(int cmd, char abyte, int port);

程序例:

#include

#include

#define COM1       0

#define DATA_READY 0x100

#define TRUE       1

#define FALSE      0

#define SETTINGS ( 0x80 | 0x02 | 0x00 | 0x00)

int main(void)

{

   int in, out, status, DONE = FALSE;

   bioscom(0, SETTINGS, COM1);

   cprintf("... BIOSCOM [ESC] to exit ...\n");

   while (!DONE)

   {

      status = bioscom(3, 0, COM1);

      if (status & DATA_READY)

  if ((out = bioscom(2, 0, COM1) & 0x7F) != 0)

     putch(out);

  if (kbhit())

  {

     if ((in = getch()) == '\x1B')

        DONE = TRUE;

     bioscom(1, in, COM1);

  }

   }

   return 0;

}

函数名: biosdisk

功  能: 软硬盘I/O

用  法: int biosdisk(int cmd, int drive, int head, int track, int sector

       int nsects, void *buffer);

程序例:

#include

#include

int main(void)

{

   int result;

   char buffer[512];

   printf("Testing to see if drive a: is ready\n");

   result = biosdisk(4,0,0,0,0,1,buffer);

   result &= 0x02;

   (result) ? (printf("Drive A: Ready\n")) :

       (printf("Drive A: Not Ready\n"));

   return 0;

}

函数名: biosequip

功  能: 检查设备

用  法: int biosequip(void);

程序例:

#include

#include

int main(void)

{

   int result;

   char buffer[512];

   printf("Testing to see if drive a: is ready\n");

   result = biosdisk(4,0,0,0,0,1,buffer);

   result &= 0x02;

   (result) ? (printf("Drive A: Ready\n")) :

       (printf("Drive A: Not Ready\n"));

   return 0;

}

函数名: bioskey

功  能: 直接使用BIOS服务的键盘接口

用  法: int bioskey(int cmd);

程序例:

#include

#include

#include

#define RIGHT  0x01

#define LEFT   0x02

#define CTRL   0x04

#define ALT    0x08

int main(void)

{

   int key, modifiers;

   /* function 1 returns 0 until a key is pressed */

   while (bioskey(1) == 0);

   /* function 0 returns the key that is waiting */

   key = bioskey(0);

   /* use function 2 to determine if shift keys were used */

   modifiers = bioskey(2);

   if (modifiers)

   {

      printf("[");

      if (modifiers & RIGHT) printf("RIGHT");

      if (modifiers & LEFT)  printf("LEFT");

      if (modifiers & CTRL)  printf("CTRL");

      if (modifiers & ALT)    printf("ALT");

      printf("]");

   }

   /* print out the character read */

   if (isalnum(key & 0xFF))

      printf("'%c'\n", key);

   else

      printf("%#02x\n", key);

   return 0;

}

函数名: biosmemory

功  能: 返回存储块大小

用  法:int biosmemory(void);

程序例:

#include

#include

int main(void)

{

   int memory_size;

   memory_size = biosmemory();  /* returns value up to 640K */

   printf("RAM size = %dK\n",memory_size);

   return 0;

}

函数名: biosprint

功  能: 直接使用BIOS服务的打印机I/O

用  法: int biosprint(int cmd, int byte, int port);

程序例:

#include

#include

#include

int main(void)

{

   #define STATUS  2    /* printer status command */

   #define PORTNUM 0    /* port number for LPT1 */

   int status, abyte=0;

   printf("Please turn off your printer.  Press any key to continue\n");

   getch();

   status = biosprint(STATUS, abyte, PORTNUM);

   if (status & 0x01)

      printf("Device time out.\n");

   if (status & 0x08)

      printf("I/O error.\n");

   if (status & 0x10)

      printf("Selected.\n");

   if (status & 0x20)

      printf("Out of paper.\n");

   if (status & 0x40)

      printf("Acknowledge.\n");

   if (status & 0x80)

      printf("Not busy.\n");

   return 0;

}

函数名: biostime

功  能: 读取或设置BIOS时间

用  法: long biostime(int cmd, long newtime);

程序例:

#include

#include

#include

#include

int main(void)

{

   long bios_time;

   clrscr();

   cprintf("The number of clock ticks since midnight is:\r\n");

   cprintf("The number of seconds since midnight is:\r\n");

   cprintf("The number of minutes since midnight is:\r\n");

   cprintf("The number of hours since midnight is:\r\n");

   cprintf("\r\nPress any key to quit:");

   while(!kbhit())

   {

      bios_time = biostime(0, 0L);

      gotoxy(50, 1);

      cprintf("%lu", bios_time);

      gotoxy(50, 2);

      cprintf("%.4f", bios_time / CLK_TCK);

      gotoxy(50, 3);

      cprintf("%.4f", bios_time / CLK_TCK / 60);

      gotoxy(50, 4);

      cprintf("%.4f", bios_time / CLK_TCK / 3600);

   }

   return 0;

}

函数名: brk

功  能: 改变数据段空间分配

用  法: int brk(void *endds);

程序例:

#include

#include

int main(void)

{

   char *ptr;

   printf("Changing allocation with brk()\n");

   ptr = malloc(1);

   printf("Before brk() call: %lu bytes free\n", coreleft());

   brk(ptr+1000);

   printf(" After brk() call: %lu bytes free\n", coreleft());

   return 0;

}

函数名: bsearch

功  能: 二分法搜索

用  法: void *bsearch(const void *key, const void *base, size_t *nelem,

        size_t width, int(*fcmp)(const void *, const *));

程序例:

#include

#include

#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))

int numarray[] = {123, 145, 512, 627, 800, 933};

int numeric (const int *p1, const int *p2)

{

   return(*p1 - *p2);

}

int lookup(int key)

{

   int *itemptr;

   /* The cast of (int(*)(const void *,const void*))

      is needed to avoid a type mismatch error at

      compile time */

   itemptr = bsearch (&key, numarray, NELEMS(numarray),

      sizeof(int), (int(*)(const void *,const void *))numeric);

   return (itemptr != NULL);

}

int main(void)

{

   if (lookup(512))

      printf("512 is in the table.\n");

   else

      printf("512 isn't in the table.\n");

    return 0;

}