I开头函数
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 */
函数prototypewhile (!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");