B開頭的函數

函數名: bar
功 能: 畫一個二維條形圖
用 法: void far bar(int left, int top, int right, int bottom);
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 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<USER_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; }


函數名: bar3d
功 能: 畫一個三維條形圖
用 法: void far bar3d(int left, int top, int right, int bottom,
int depth, int topflag);
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 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<USER_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; }


函數名: bdos
功 能: DOS系統調用
用 法: int bdos(int dosfun, unsigned dosdx, unsigned dosal);
程序例:

#include <stdio.h> #include <dos.h> /* 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; }


函數名: bdosptr
功 能: DOS系統調用
用 法: int bdosptr(int dosfun, void *argument, unsigned dosal);
程序例:

#include <string.h> #include <stdio.h> #include <dir.h> #include <dos.h> #include <errno.h> #include <stdlib.h> #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; }


函數名: bioscom
功 能: 串行I/O通信
用 法: int bioscom(int cmd, char abyte, int port);
程序例:

#include <bios.h> #include <conio.h> #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; }


函數名: biosdisk
功 能: 軟硬盤I/O
用 法: int biosdisk(int cmd, int drive, int head, int track, int sector
int nsects, void *buffer);
程序例:

#include <bios.h> #include <stdio.h> 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; }


函數名: biosequip
功 能: 檢查設備
用 法: int biosequip(void);
程序例:

#include <bios.h> #include <stdio.h> 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; }


函數名: bioskey
功 能: 直接使用BIOS服務的鍵盤接口
用 法: int bioskey(int cmd);
程序例:

#include <stdio.h> #include <bios.h> #include <ctype.h> #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; }


函數名: biosmemory
功 能: 返回存儲塊大小
用 法:int biosmemory(void);
程序例:

#include <stdio.h> #include <bios.h> int main(void) { int memory_size; memory_size = biosmemory(); /* returns value up to 640K */ printf("RAM size = %dK\n",memory_size); return 0; }


函數名: biosprint
功 能: 直接使用BIOS服務的打印機I/O
用 法: int biosprint(int cmd, int byte, int port);
程序例:

#include <stdio.h> #include <conio.h> #include <bios.h> 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; }


函數名: biostime
功 能: 讀取或設置BIOS時間
用 法: long biostime(int cmd, long newtime);
程序例:

#include <stdio.h> #include <bios.h> #include <time.h> #include <conio.h> 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; }


函數名: brk
功 能: 改變數據段空間分配
用 法: int brk(void *endds);
程序例:

#include <stdio.h> #include <alloc.h> 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; }


函數名: 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 <stdlib.h> #include <stdio.h> #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; }