c语言函数---I

函数名: imagesize

功 能: 返回保存位图像所需的字节数

用 法: unsigned far imagesize(int left, int top, int right, int bottom);

程序例:

#include <graphics.h> 
#include <stdlib.h> 
#include <stdio.h> 
#include <conio.h> 
#define ARROW_SIZE 10 
void draw_arrow(int x, int y); 
int main(void) 
{ 
   /* request autodetection */ 
   int gdriver = DETECT, gmode, errorcode; 
   void *arrow; 
   int x, y, maxx; 
   unsigned int size; 
   /* 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 */ 
   } 
   maxx = getmaxx(); 
   x = 0; 
   y = getmaxy() / 2; 
   /* draw the image to be grabbed */ 
   draw_arrow(x, y); 
   /* calculate the size of the image */ 
   size = imagesize(x, y-ARROW_SIZE, x+(4*ARROW_SIZE), y+ARROW_SIZE); 
   /* allocate memory to hold the image */ 
   arrow = malloc(size); 
   /* grab the image */ 
   getimage(x, y-ARROW_SIZE, x+(4*ARROW_SIZE), y+ARROW_SIZE, arrow); 
   /* repeat until a key is pressed */ 
   while (!kbhit()) 
   { 
      /* erase old image */ 
      putimage(x, y-ARROW_SIZE, arrow, XOR_PUT); 
      x += ARROW_SIZE; 
      if (x >= maxx) 
          x = 0; 
      /* plot new image */ 
      putimage(x, y-ARROW_SIZE, arrow, XOR_PUT); 
   } 
   /* clean up */ 
   free(arrow); 
   closegraph(); 
   return 0; 
} 
void draw_arrow(int x, int y) 
{ 
   /* draw an arrow on the screen */ 
   moveto(x, y); 
   linerel(4*ARROW_SIZE, 0); 
   linerel(-2*ARROW_SIZE, -1*ARROW_SIZE); 
   linerel(0, 2*ARROW_SIZE); 
   linerel(2*ARROW_SIZE, -1*ARROW_SIZE); 
} 
  
  
  

函数名: initgraph

功 能: 初始化图形系统

用 法: void far initgraph(int far *graphdriver, int far *graphmode,

    char far *pathtodriver); 

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 mode */ 
   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);             /* return with error code */ 
   } 
   /* draw a line */ 
   line(0, 0, getmaxx(), getmaxy()); 
   /* clean up */ 
   getch(); 
   closegraph(); 
   return 0; 
} 
  
  

函数名: inport

功 能: 从硬件端口中输入

用 法: int inp(int protid);

程序例:

#include <stdio.h> 
#include <dos.h> 
int main(void) 
{ 
   int result; 
   int port = 0;  /* serial port 0 */ 
   result = inport(port); 
   printf("Word read from port %d = 0x%X\n", port, result); 
   return 0; 
} 
  
  

函数名: insline

功 能: 在文本窗口中插入一个空行

用 法: void insline(void);

程序例:

#include <conio.h> 
int main(void) 
{ 
   clrscr(); 
   cprintf("INSLINE inserts an empty line in the text window\r\n"); 
   cprintf("at the cursor position using the current text\r\n"); 
   cprintf("background color.  All lines below the empty one\r\n"); 
   cprintf("move down one line and the bottom line scrolls\r\n"); 
   cprintf("off the bottom of the window.\r\n"); 
   cprintf("\r\nPress any key to continue:"); 
   gotoxy(1, 3); 
   getch(); 
   insline(); 
   getch(); 
   return 0; 
} 
  
  
  

函数名: installuserdriver

功 能: 安装设备驱动程序到BGI设备驱动程序表中

用 法: int far installuserdriver(char far *name, int (*detect)(void));

程序例:

#include <graphics.h> 
#include <stdlib.h> 
#include <stdio.h> 
#include <conio.h> 
/* function prototypes */ 
int huge detectEGA(void); 
void checkerrors(void); 
int main(void) 
{ 
   int gdriver, gmode; 
   /* install a user written device driver */ 
   gdriver = installuserdriver("EGA", detectEGA); 
   /* must force use of detection routine */ 
   gdriver = DETECT; 
   /* check for any installation errors */ 
   checkerrors(); 
   /* initialize graphics and local variables */ 
   initgraph(&gdriver, &gmode, ""); 
   /* check for any initialization errors */ 
   checkerrors(); 
   /* draw a line */ 
   line(0, 0, getmaxx(), getmaxy()); 
   /* clean up */ 
   getch(); 
   closegraph(); 
   return 0; 
} 
/* detects EGA or VGA cards */ 
int huge detectEGA(void) 
{ 
   int driver, mode, sugmode = 0; 
   detectgraph(&driver, &mode); 
   if ((driver == EGA) || (driver == VGA)) 
      /* return suggested video mode number */ 
      return sugmode; 
   else 
      /* return an error code */ 
      return grError; 
} 
/* check for and report any graphics errors */ 
void checkerrors(void) 
{ 
   int errorcode; 
   /* read result of last graphics operation */ 
   errorcode = graphresult(); 
   if (errorcode != grOk) 
   { 
      printf("Graphics error: %s\n", grapherrormsg(errorcode)); 
      printf("Press any key to halt:"); 
      getch(); 
      exit(1); 
   } 
} 

函数名: installuserfont

功 能: 安装未嵌入BGI系统的字体文件(CHR)

用 法: int far installuserfont(char far *name);

程序例:

#include <graphics.h> 
#include <stdlib.h> 
#include <stdio.h> 
#include <conio.h> 
/* function prototype */ 
void checkerrors(void); 
int main(void) 
{ 
   /* request auto detection */ 
   int gdriver = DETECT, gmode; 
   int userfont; 
   int midx, midy; 
   /* initialize graphics and local variables */ 
   initgraph(&gdriver, &gmode, ""); 
   midx = getmaxx() / 2; 
   midy = getmaxy() / 2; 
   /* check for any initialization errors */ 
   checkerrors(); 
   /* install a user defined font file */ 
   userfont = installuserfont("USER.CHR"); 
   /* check for any installation errors */ 
   checkerrors(); 
   /* select the user font */ 
   settextstyle(userfont, HORIZ_DIR, 4); 
   /* output some text */ 
   outtextxy(midx, midy, "Testing!"); 
   /* clean up */ 
   getch(); 
   closegraph(); 
   return 0; 
} 
/* check for and report any graphics errors */ 
void checkerrors(void) 
{ 
   int errorcode; 
   /* read result of last graphics operation */ 
   errorcode = graphresult(); 
   if (errorcode != grOk) 
   { 
      printf("Graphics error: %s\n", grapherrormsg(errorcode)); 
      printf("Press any key to halt:"); 
      getch(); 
      exit(1); 
   } 
 } 
  
  
  

函数名: int86

功 能: 通用8086软中断接口

用 法: int int86(int intr_num, union REGS *inregs, union REGS *outregs);

程序例:

#include <stdio.h> 
#include <conio.h> 
#include <dos.h> 
#define VIDEO 0x10 
void movetoxy(int x, int y) 
{ 
   union REGS regs; 
   regs.h.ah = 2;  /* set cursor postion */ 
   regs.h.dh = y; 
   regs.h.dl = x; 
   regs.h.bh = 0;  /* video page 0 */ 
   int86(VIDEO, &regs, &regs); 
} 
int main(void) 
{ 
   clrscr(); 
   movetoxy(35, 10); 
   printf("Hello\n"); 
   return 0; 
} 
  
  

函数名: int86x

功 能: 通用8086软中断接口

用 法: int int86x(int intr_num, union REGS *insegs, union REGS *outregs,

     struct SREGS *segregs); 

程序例:

#include <dos.h> 
#include <process.h> 
#include <stdio.h> 
int main(void) 
{ 
   char filename[80]; 
   union REGS inregs, outregs; 
   struct SREGS segregs; 
   printf("Enter filename: "); 
   gets(filename); 
   inregs.h.ah = 0x43; 
   inregs.h.al = 0x21; 
   inregs.x.dx = FP_OFF(filename); 
   segregs.ds = FP_SEG(filename); 
   int86x(0x21, &inregs, &outregs, &segregs); 
   printf("File attribute: %X\n", outregs.x.cx); 
   return 0; 
} 
  
  
  

函数名: intdos

功 能: 通用DOS接口

用 法: int intdos(union REGS *inregs, union REGS *outregs);

程序例:

#include <stdio.h> 
#include <dos.h> 
/* deletes file name; returns 0 on success, nonzero on failure */ 
int delete_file(char near *filename) 
{ 
   union REGS regs; 
   int ret; 
   regs.h.ah = 0x41;                            /* delete file */ 
   regs.x.dx = (unsigned) filename; 
   ret = intdos(&regs, &regs); 
   /* if carry flag is set, there was an error */ 
   return(regs.x.cflag ? ret : 0); 
} 
int main(void) 
{ 
   int err; 
   err = delete_file("NOTEXIST.$$$"); 
   if (!err) 
      printf("Able to delete NOTEXIST.$$$\n"); 
   else 
      printf("Not Able to delete NOTEXIST.$$$\n"); 
   return 0; 
} 
  
  
  

函数名: intdosx

功 能: 通用DOS中断接口

用 法: int intdosx(union REGS *inregs, union REGS *outregs,

      struct SREGS *segregs); 

程序例:

#include <stdio.h> 
#include <dos.h> 
/* deletes file name; returns 0 on success, nonzero on failure */ 
int delete_file(char far *filename) 
{ 
   union REGS regs; struct SREGS sregs; 
   int ret; 
   regs.h.ah = 0x41;                      /* delete file */ 
   regs.x.dx = FP_OFF(filename); 
   sregs.ds = FP_SEG(filename); 
   ret = intdosx(&regs, &regs, &sregs); 
   /* if carry flag is set, there was an error */ 
   return(regs.x.cflag ? ret : 0); 
} 
int main(void) 
{ 
   int err; 
   err = delete_file("NOTEXIST.$$$"); 
   if (!err) 
      printf("Able to delete NOTEXIST.$$$\n"); 
   else 
      printf("Not Able to delete NOTEXIST.$$$\n"); 
   return 0; 
} 
  
  

函数名: intr

功 能: 改变软中断接口

用 法: void intr(int intr_num, struct REGPACK *preg);

程序例:

#include <stdio.h> 
#include <string.h> 
#include <dir.h> 
#include <dos.h> 
#define CF 1  /* Carry flag */ 
int main(void) 
{ 
   char directory[80]; 
   struct REGPACK reg; 
   printf("Enter directory to change to: "); 
   gets(directory); 
   reg.r_ax = 0x3B << 8;         /* shift 3Bh into  AH */ 
   reg.r_dx = FP_OFF(directory); 
   reg.r_ds = FP_SEG(directory); 
   intr(0x21, ?); 
   if (reg.r_flags & CF) 
      printf("Directory change failed\n"); 
   getcwd(directory, 80); 
   printf("The current directory is: %s\n", directory); 
   return 0; 
} 
  
  

函数名: ioctl

功 能: 控制I/O设备

用 法: int ioctl(int handle, int cmd[,int *argdx, int argcx]);

程序例:

#include <stdio.h> 
#include <dir.h> 
#include <io.h> 
int main(void) 
{ 
   int stat; 
   /* use func 8 to determine if the default drive is removable */ 
   stat = ioctl(0, 8, 0, 0); 
   if (!stat) 
      printf("Drive %c is removable.\n", getdisk() + ‘A‘); 
   else 
      printf("Drive %c is not removable.\n", getdisk() + ‘A‘); 
   return 0; 
} 
  
  
  

函数名: isatty

功 能: 检查设备类型

用 法: int isatty(int handle);

程序例:

#include <stdio.h> 
#include <io.h> 
int main(void) 
{ 
   int handle; 
   handle = fileno(stdprn); 
   if (isatty(handle)) 
      printf("Handle %d is a device type\n", handle); 
   else 
      printf("Handle %d isn‘t a device type\n", handle); 
   return 0; 
} 
  
  
  

函数名: itoa

功 能: 把一整数转换为字符串

用 法: char *itoa(int value, char *string, int radix);

程序例:

#include <stdlib.h> 
#include <stdio.h> 
int main(void) 
{ 
   int number = 12345; 
   char string[25]; 
   itoa(number, string, 10); 
   printf("integer = %d string = %s\n", number, string); 
   return 0; 
}