C语言函数集（八）

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, ®s, ®s);
}

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(®s, ®s);

/* 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(®s, ®s, &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;
}