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port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: 在文本窗体中插入一个空行

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;
} 

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