📄 023.htm
字号:
<HTML><HEAD><meta http-equiv="Content-Type" content="text/html; charset=GB2312"><TITLE>王大刚-->C语言编程宝典-->D</TITLE>
<META NAME="keywords" CONTENT="王大刚 C语言编程宝典 D">
<META NAME="description" CONTENT="王大刚 - C语言编程宝典 - D">
<style>
<!--
#page {position:absolute; z-index:0; left:0px; top:0px}
.tt3 {font: 9pt/12pt "宋体"}
.tt2 {font: 12pt/15pt "宋体"}
a {text-decoration:none}
a:hover {color: blue;text-decoration:underline}
-->
</style>
</HEAD>
<body text="#000000" aLink=#9900ff link=#006699 vLink=#006699 bgcolor="#FFFFFF" leftmargin="3" topmargin="3" marginheight="3" marginwidth="3">
<TABLE WIDTH="100%" CELLPADDING=10 CELLSPACING=0 BORDER=0>
<TR>
<TD CLASS="tt3" VALIGN="top" width="8%" bgcolor="#e0e0e0"><strong><A HREF="024.htm">后一页</A><BR>
<A HREF="022.htm">前一页</A><BR>
<A HREF="index.html">回目录</A><BR>
<A HREF="../../../../index.htm">回首页</A><BR>
</strong>
</TD>
<TD class="tt2" bgcolor="#F5F8F8" width="84%"><center><B><FONT style="FONT-SIZE: 16.5pt" COLOR="#FF6666" FACE="楷体_GB2312">D</FONT></B></center>
<hr color="#EE9B73" size="1" width="94%">
<P>函数名: delay
<BR>功 能: 将程序的执行暂停一段时间(毫秒)
<BR>用 法: void delay(unsigned milliseconds);
<BR>程序例:
<BR>/* Emits a 440-Hz tone for 500 milliseconds */
<BR>#include <dos.h>
<BR>
<P>int main(void)
<BR>{
<BR> sound(440);
<BR> delay(500);
<BR> nosound();
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<BR>
<P>函数名: delline
<BR>功 能: 在文本窗口中删去一行
<BR>用 法: void delline(void);
<BR>程序例:
<BR>
<P>#include <conio.h>
<BR>
<P>int main(void)
<BR>{
<BR> clrscr();
<BR> cprintf("The function DELLINE deletes \
<BR> the line containing the\r\n");
<BR> cprintf("cursor and moves all lines \
<BR> below it one line up.\r\n");
<BR> cprintf("DELLINE operates within the \
<BR> currently active text\r\n");
<BR> cprintf("window. Press any key to \
<BR> continue . . .");
<BR> gotoxy(1,2); /* Move the cursor to the
<BR> second line and first column */
<BR> getch();
<BR>
<P> delline();
<BR> getch();
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<P>函数名: detectgraph
<BR>功 能: 通过检测硬件确定图形驱动程序和模式
<BR>用 法: void far detectgraph(int far *graphdriver, int far *graphmode);
<BR>程序例:
<BR>
<P>#include <graphics.h>
<BR>#include <stdlib.h>
<BR>#include <stdio.h>
<BR>#include <conio.h>
<BR>
<P>/* names of the various cards supported */
<BR>char *dname[] = { "requests detection",
<BR> "a CGA",
<BR> "an MCGA",
<BR> "an EGA",
<BR> "a 64K EGA",
<BR> "a monochrome EGA",
<BR> "an IBM 8514",
<BR> "a Hercules monochrome",
<BR> "an AT&T 6300 PC",
<BR> "a VGA",
<BR> "an IBM 3270 PC"
<BR> };
<BR>
<P>int main(void)
<BR>{
<BR> /* returns detected hardware info. */
<BR> int gdriver, gmode, errorcode;
<BR>
<P> /* detect graphics hardware available */
<BR> detectgraph(&gdriver, &gmode);
<BR>
<P> /* read result of detectgraph call */
<BR> errorcode = graphresult();
<BR> if (errorcode != grOk) /* an error
<BR> occurred */
<BR> {
<BR> printf("Graphics error: %s\n", \
<BR> grapherrormsg(errorcode));
<BR> printf("Press any key to halt:");
<BR> getch();
<BR> exit(1); /* terminate with an error
<BR> code */
<BR> }
<BR>
<P> /* display the information detected */
<BR> clrscr();
<BR> printf("You have %s video display \
<BR> card.\n", dname[gdriver]);
<BR> printf("Press any key to halt:");
<BR> getch();
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: difftime
<BR>功 能: 计算两个时刻之间的时间差
<BR>用 法: double difftime(time_t time2, time_t time1);
<BR>程序例:
<BR>
<P>#include <time.h>
<BR>#include <stdio.h>
<BR>#include <dos.h>
<BR>#include <conio.h>
<BR>
<P>int main(void)
<BR>{
<BR> time_t first, second;
<BR>
<P> clrscr();
<BR> first = time(NULL); /* Gets system
<BR> time */
<BR> delay(2000);
/* Waits 2 secs */
<BR> second = time(NULL); /* Gets system time
<BR> again */
<BR>
<P> printf("The difference is: %f \
<BR> seconds\n",difftime(second,first));
<BR> getch();
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<BR>
<P>函数名: disable
<BR>功 能: 屏蔽中断
<BR>用 法: void disable(void);
<BR>程序例:
<BR>
<P>/***NOTE: This is an interrupt service
<BR> routine. You cannot compile this program
<BR> with Test Stack Overflow turned on and
<BR> get an executable file that operates
<BR> correctly. */
<BR>
<P>#include <stdio.h>
<BR>#include <dos.h>
<BR>#include <conio.h>
<BR>
<P>#define INTR 0X1C /* The clock tick
<BR> interrupt */
<BR>
<P>void interrupt ( *oldhandler)(void);
<BR>
<P>int count=0;
<BR>
<P>void interrupt handler(void)
<BR>{
<BR>/* disable interrupts during the handling of
<BR> the interrupt */
<BR> disable();
<BR>/* increase the global counter */
<BR> count++;
<BR>/* reenable interrupts at the end of the
<BR> handler */
<BR> enable();
<BR>/* call the old routine */
<BR> oldhandler();
<BR>}
<BR>
<P>int main(void)
<BR>{
<BR>/* save the old interrupt vector */
<BR> oldhandler = getvect(INTR);
<BR>
<P>/* install the new interrupt handler */
<BR> setvect(INTR, handler);
<BR>
<P>/* loop until the counter exceeds 20 */
<BR> while (count < 20)
<BR> printf("count is %d\n",count);
<BR>
<P>/* reset the old interrupt handler */
<BR> setvect(INTR, oldhandler);
<BR>
<P> return 0;
<BR>}
<BR>
<P>函数名: div
<BR>功 能: 将两个整数相除, 返回商和余数
<BR>用 法: div_t (int number, int denom);
<BR>程序例:
<BR>
<P>#include <stdlib.h>
<BR>#include <stdio.h>
<BR>
<P>div_t x;
<BR>
<P>int main(void)
<BR>{
<BR> x = div(10,3);
<BR> printf("10 div 3 = %d remainder %d\n", x.quot, x.rem);
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<BR>
<P>函数名: dosexterr
<BR>功 能: 获取扩展DOS错误信息
<BR>用 法: int dosexterr(struct DOSERR *dblkp);
<BR>程序例:
<BR>
<P>#include <stdio.h>
<BR>#include <dos.h>
<BR>
<P>int main(void)
<BR>{
<BR> FILE *fp;
<BR> struct DOSERROR info;
<BR>
<P> fp = fopen("perror.dat","r");
<BR> if (!fp) perror("Unable to open file for
<BR> reading");
<BR> dosexterr(&info);
<BR>
<P> printf("Extended DOS error \
<BR> information:\n");
<BR> printf(" Extended error: \
<BR> %d\n",info.exterror);
<BR> printf("
Class: \
<BR> %x\n",info.class);
<BR> printf("
Action: \
<BR> %x\n",info.action);
<BR> printf(" Error Locus: \
<BR> %x\n",info.locus);
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<BR>
<P>函数名: dostounix
<BR>功 能: 转换日期和时间为UNIX时间格式
<BR>用 法: long dostounix(struct date *dateptr, struct time *timeptr);
<BR>程序例:
<BR>
<P> #include <time.h>
<BR> #include <stddef.h>
<BR> #include <dos.h>
<BR> #include <stdio.h>
<BR>
<P> int main(void)
<BR> {
<BR> time_t t;
<BR> struct time d_time;
<BR> struct date d_date;
<BR> struct tm *local;
<BR>
<P> getdate(&d_date);
<BR> gettime(&d_time);
<BR>
<P> t = dostounix(&d_date, &d_time);
<BR> local = localtime(&t);
<BR> printf("Time and Date: %s\n", \
<BR> asctime(local));
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<BR>
<P>函数名: drawpoly
<BR>功 能: 画多边形
<BR>用 法: void far drawpoly(int numpoints, int far *polypoints);
<BR>程序例:
<BR>
<P>#include <graphics.h>
<BR>#include <stdlib.h>
<BR>#include <stdio.h>
<BR>#include <conio.h>
<BR>
<P>int main(void)
<BR>{
<BR> /* request auto detection */
<BR> int gdriver = DETECT, gmode, errorcode;
<BR> int maxx, maxy;
<BR>
<P> /* our polygon array */
<BR> int poly[10];
<BR>
<P> /* initialize graphics and local
<BR> variables */
<BR> initgraph(&gdriver, &gmode, "");
<BR>
<P> /* read result of initialization */
<BR> errorcode = graphresult();
<BR> if (errorcode != grOk)
<BR> /* an error occurred */
<BR> {
<BR> printf("Graphics error: %s\n", \
<BR> grapherrormsg(errorcode));
<BR> printf("Press any key to halt:");
<BR> getch();
<BR> /* terminate with an error code */
<BR> exit(1);
<BR> }
<BR>
<P> maxx = getmaxx();
<BR> maxy = getmaxy();
<BR>
<P> poly[0] = 20;
/* 1st vertext */
<BR> poly[1] = maxy / 2;
<BR>
<P> poly[2] = maxx - 20; /* 2nd */
<BR> poly[3] = 20;
<BR>
<P> poly[4] = maxx - 50; /* 3rd */
<BR> poly[5] = maxy - 20;
<BR>
<P> poly[6] = maxx / 2; /* 4th */
<BR> poly[7] = maxy / 2;
<BR>/*
<BR> drawpoly doesn't automatically close
<BR> the polygon, so we close it.
<BR>*/
<BR> poly[8] = poly[0];
<BR> poly[9] = poly[1];
<BR>
<P> /* draw the polygon */
<BR> drawpoly(5, poly);
<BR>
<P> /* clean up */
<BR> getch();
<BR> closegraph();
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<P>函数名: dup
<BR>功 能: 复制一个文件句柄
<BR>用 法: int dup(int handle);
<BR>程序例:
<BR>
<P>#include <string.h>
<BR>#include <stdio.h>
<BR>#include <conio.h>
<BR>#include <io.h>
<BR>
<P>void flush(FILE *stream);
<BR>
<P>int main(void)
<BR>{
<BR> FILE *fp;
<BR> char msg[] = "This is a test";
<BR>
<P> /* create a file */
<BR> fp = fopen("DUMMY.FIL", "w");
<BR>
<P> /* write some data to the file */
<BR> fwrite(msg, strlen(msg), 1, fp);
<BR>
<P> clrscr();
<BR> printf("Press any key to flush \
<BR> DUMMY.FIL:");
<BR> getch();
<BR>
<P> /* flush the data to DUMMY.FIL without
<BR> closing it */
<BR> flush(fp);
<BR>
<P> printf("\nFile was flushed, Press any \
<BR> key to quit:");
<BR> getch();
<BR> return 0;
<BR>}
<BR>
<P>void flush(FILE *stream)
<BR>{
<BR> int duphandle;
<BR>
<P> /* flush TC's internal buffer */
<BR> fflush(stream);
<BR>
<P> /* make a duplicate file handle */
<BR> duphandle = dup(fileno(stream));
<BR>
<P> /* close the duplicate handle to flush the
<BR> DOS buffer */
<BR> close(duphandle);
<BR>}
<BR>
<BR>
<BR>
<P>函数名: dup2
<BR>功 能: 复制文件句柄
<BR>用 法: int dup2(int oldhandle, int newhandle);
<BR>程序例:
<BR>
<P>#include <sys\stat.h>
<BR>#include <string.h>
<BR>#include <fcntl.h>
<BR>#include <io.h>
<BR>
<P>int main(void)
<BR>{
<BR> #define STDOUT 1
<BR>
<P> int nul, oldstdout;
<BR> char msg[] = "This is a test";
<BR>
<P> /* create a file */
<BR> nul = open("DUMMY.FIL", O_CREAT | O_RDWR,
<BR> S_IREAD | S_IWRITE);
<BR>
<P> /* create a duplicate handle for standard
<BR> output */
<BR> oldstdout = dup(STDOUT);
<BR> /*
<BR> redirect standard output to DUMMY.FIL
<BR> by duplicating the file handle onto
the
<BR> file handle for standard output.
<BR> */
<BR> dup2(nul, STDOUT);
<BR>
<P> /* close the handle for DUMMY.FIL */
<BR> close(nul);
<BR>
<P> /* will be redirected into DUMMY.FIL */
<BR> write(STDOUT, msg, strlen(msg));
<BR>
<P> /* restore original standard output
<BR> handle */
<BR> dup2(oldstdout, STDOUT);
<BR>
<P> /* close duplicate handle for STDOUT */
<BR> close(oldstdout);
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<hr color="#EE9B73" size="1" width="94%">
</TD>
<TD CLASS="tt3" VALIGN="bottom" width="8%" bgcolor="#e0e0e0"><strong><A HREF="024.htm">后一页</A><BR>
<A HREF="022.htm">前一页</A><BR>
<A HREF="index.html">回目录</A><BR>
<A HREF="../../../../index.htm">回首页</A><BR>
</strong>
</TD>
</TR>
</table>
</BODY></HTML>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -