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<br>函数名: raise
<br>功 能: 向正在执行的程序发送一个信号
<br>用 法: int raise(int sig);
<br>程序例:
<br>
<br>#include <signal.h>
<br>
<br>int main(void)
<br>{
<br> int a, b;
<br>
<br> a = 10;
<br> b = 0;
<br> if (b == 0)
<br> /* preempt divide by zero error */
<br> raise(SIGFPE);
<br> a = a / b;
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: rand
<br>功 能: 随机数发生器
<br>用 法: void rand(void);
<br>程序例:
<br>
<br>#include <stdlib.h>
<br>#include <stdio.h>
<br>
<br>int main(void)
<br>{
<br> int i;
<br>
<br> printf("Ten random numbers from 0 to 99\n\n");
<br> for(i=0; i<10; i++)
<br> printf("%d\n", rand() % 100);
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: randbrd
<br>功 能: 随机块读
<br>用 法: int randbrd(struct fcb *fcbptr, int reccnt);
<br>程序例:
<br>
<br>#include <process.h>
<br>#include <string.h>
<br>#include <stdio.h>
<br>#include <dos.h>
<br>
<br>int main(void)
<br>{
<br> char far *save_dta;
<br> char line[80], buffer[256];
<br> struct fcb blk;
<br> int i, result;
<br>
<br> /* get user input file name for dta */
<br> printf("Enter drive and file name (no path - i.e. a:file.dat)\n");
<br> gets(line);
<br>
<br> /* put file name in fcb */
<br> if (!parsfnm(line, &blk, 1))
<br> {
<br> printf("Error in call to parsfnm\n");
<br> exit(1);
<br> }
<br> printf("Drive #%d File: %s\n\n", blk.fcb_drive, blk.fcb_name);
<br>
<br> /* open file with DOS FCB open file */
<br> bdosptr(0x0F, &blk, 0);
<br>
<br> /* save old dta, and set new one */
<br> save_dta = getdta();
<br> setdta(buffer);
<br>
<br> /* set up info for the new dta */
<br> blk.fcb_recsize = 128;
<br> blk.fcb_random = 0L;
<br> result = randbrd(&blk, 1);
<br>
<br> /* check results from randbrd */
<br> if (!result)
<br> printf("Read OK\n\n");
<br> else
<br> {
<br> perror("Error during read");
<br> exit(1);
<br> }
<br>
<br> /* read in data from the new dta */
<br> printf("The first 128 characters are:\n");
<br> for (i=0; i<128; i++)
<br> putchar(buffer[i]);
<br>
<br> /* restore previous dta */
<br> setdta(save_dta);
<br>
<br> return 0;
<br>}
<br>
<br>
<br>函数名: randbwr
<br>功 能: 随机块写
<br>用 法: int randbwr(struct fcp *fcbptr, int reccnt);
<br>程序例:
<br>
<br>#include <process.h>
<br>#include <string.h>
<br>#include <stdio.h>
<br>#include <dos.h>
<br>
<br>int main(void)
<br>{
<br> char far *save_dta;
<br> char line[80];
<br> char buffer[256] = "RANDBWR test!";
<br> struct fcb blk;
<br> int result;
<br>
<br> /* get new file name from user */
<br> printf("Enter a file name to create (no path - ie. a:file.dat\n");
<br> gets(line);
<br>
<br> /* parse the new file name to the dta */
<br> parsfnm(line,&blk,1);
<br> printf("Drive #%d File: %s\n", blk.fcb_drive, blk.fcb_name);
<br>
<br> /* request DOS services to create file */
<br> if (bdosptr(0x16, &blk, 0) == -1)
<br> {
<br> perror("Error creating file");
<br> exit(1);
<br> }
<br>
<br> /* save old dta and set new dta */
<br> save_dta = getdta();
<br> setdta(buffer);
<br>
<br> /* write new records */
<br> blk.fcb_recsize = 256;
<br> blk.fcb_random = 0L;
<br> result = randbwr(&blk, 1);
<br>
<br> if (!result)
<br> printf("Write OK\n");
<br> else
<br> {
<br> perror("Disk error");
<br> exit(1);
<br> }
<br>
<br> /* request DOS services to close the file */
<br> if (bdosptr(0x10, &blk, 0) == -1)
<br> {
<br> perror("Error closing file");
<br> exit(1);
<br> }
<br>
<br> /* reset the old dta */
<br> setdta(save_dta);
<br>
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: random
<br>功 能: 随机数发生器
<br>用 法: int random(int num);
<br>程序例:
<br>
<br>#include <stdlib.h>
<br>#include <stdio.h>
<br>#include <time.h>
<br>
<br>/* prints a random number in the range 0 to 99 */
<br>int main(void)
<br>{
<br> randomize();
<br> printf("Random number in the 0-99 range: %d\n", random (100));
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: randomize
<br>功 能: 初始化随机数发生器
<br>用 法: void randomize(void);
<br>程序例:
<br>
<br>#include <stdlib.h>
<br>#include <stdio.h>
<br>#include <time.h>
<br>
<br>int main(void)
<br>{
<br> int i;
<br>
<br> randomize();
<br> printf("Ten random numbers from 0 to 99\n\n");
<br> for(i=0; i<10; i++)
<br> printf("%d\n", rand() % 100);
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: read
<br>功 能: 从文件中读
<br>用 法: int read(int handle, void *buf, int nbyte);
<br>程序例:
<br>
<br>#include <stdio.h>
<br>#include <io.h>
<br>#include <alloc.h>
<br>#include <fcntl.h>
<br>#include <process.h>
<br>#include <sys\stat.h>
<br>
<br>int main(void)
<br>{
<br> void *buf;
<br> int handle, bytes;
<br>
<br> buf = malloc(10);
<br>
<br>/*
<br> Looks for a file in the current directory named TEST.$$$ and attempts
<br> to read 10 bytes from it. To use this example you should create the
<br> file TEST.$$$
<br>*/
<br> if ((handle =
<br> open("TEST.$$$", O_RDONLY | O_BINARY, S_IWRITE | S_IREAD)) == -1)
<br> {
<br> printf("Error Opening File\n");
<br> exit(1);
<br> }
<br>
<br> if ((bytes = read(handle, buf, 10)) == -1) {
<br> printf("Read Failed.\n");
<br> exit(1);
<br> }
<br> else {
<br> printf("Read: %d bytes read.\n", bytes);
<br> }
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: realloc
<br>功 能: 重新分配主存
<br>用 法: void *realloc(void *ptr, unsigned newsize);
<br>程序例:
<br>
<br>#include <stdio.h>
<br>#include <alloc.h>
<br>#include <string.h>
<br>
<br>int main(void)
<br>{
<br> char *str;
<br>
<br> /* allocate memory for string */
<br> str = malloc(10);
<br>
<br> /* copy "Hello" into string */
<br> strcpy(str, "Hello");
<br>
<br> printf("String is %s\n Address is %p\n", str, str);
<br> str = realloc(str, 20);
<br> printf("String is %s\n New address is %p\n", str, str);
<br>
<br> /* free memory */
<br> free(str);
<br>
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: rectangle
<br>功 能: 画一个矩形
<br>用 法: void far rectangle(int left, int top, int right, int bottom);
<br>程序例:
<br>
<br>#include <graphics.h>
<br>#include <stdlib.h>
<br>#include <stdio.h>
<br>#include <conio.h>
<br>
<br>int main(void)
<br>{
<br> /* request auto detection */
<br> int gdriver = DETECT, gmode, errorcode;
<br> int left, top, right, bottom;
<br>
<br> /* initialize graphics and local variables */
<br> initgraph(&gdriver, &gmode, "");
<br>
<br> /* read result of initialization */
<br> errorcode = graphresult();
<br> if (errorcode != grOk) /* an error occurred */
<br> {
<br> printf("Graphics error: %s\n", grapherrormsg(errorcode));
<br> printf("Press any key to halt:");
<br> getch();
<br> exit(1); /* terminate with an error code */
<br> }
<br>
<br> left = getmaxx() / 2 - 50;
<br> top = getmaxy() / 2 - 50;
<br> right = getmaxx() / 2 + 50;
<br> bottom = getmaxy() / 2 + 50;
<br>
<br> /* draw a rectangle */
<br> rectangle(left,top,right,bottom);
<br>
<br> /* clean up */
<br> getch();
<br> closegraph();
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: registerbgidriver
<br>功 能: 登录已连接进来的图形驱动程序代码
<br>用 法: int registerbgidriver(void(*driver)(void));
<br>程序例:
<br>
<br>#include <graphics.h>
<br>#include <stdlib.h>
<br>#include <stdio.h>
<br>#include <conio.h>
<br>
<br>int main(void)
<br>{
<br> /* request auto detection */
<br> int gdriver = DETECT, gmode, errorcode;
<br>
<br> /* register a driver that was added into graphics.lib */
<br> errorcode = registerbgidriver(EGAVGA_driver);
<br>
<br> /* report any registration errors */
<br> if (errorcode < 0)
<br> {
<br> printf("Graphics error: %s\n", grapherrormsg(errorcode));
<br> printf("Press any key to halt:");
<br> getch();
<br> exit(1); /* terminate with an error code */
<br> }
<br>
<br> /* initialize graphics and local variables */
<br> initgraph(&gdriver, &gmode, "");
<br>
<br> /* read result of initialization */
<br> errorcode = graphresult();
<br> if (errorcode != grOk) /* an error occurred */
<br> {
<br> printf("Graphics error: %s\n", grapherrormsg(errorcode));
<br> printf("Press any key to halt:");
<br> getch();
<br> exit(1); /* terminate with an error code */
<br> }
<br>
<br> /* draw a line */
<br> line(0, 0, getmaxx(), getmaxy());
<br>
<br> /* clean up */
<br> getch();
<br> closegraph();
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: remove
<br>功 能: 删除一个文件
<br>用 法: int remove(char *filename);
<br>程序例:
<br>
<br>#include <stdio.h>
<br>
<br>int main(void)
<br>{
<br> char file[80];
<br>
<br> /* prompt for file name to delete */
<br> printf("File to delete: ");
<br> gets(file);
<br>
<br> /* delete the file */
<br> if (remove(file) == 0)
<br> printf("Removed %s.\n",file);
<br> else
<br> perror("remove");
<br>
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: rename
<br>功 能: 重命名文件
<br>用 法: int rename(char *oldname, char *newname);
<br>程序例:
<br>
<br>#include <stdio.h>
<br>
<br>int main(void)
<br>{
<br> char oldname[80], newname[80];
<br>
<br> /* prompt for file to rename and new name */
<br> printf("File to rename: ");
<br> gets(oldname);
<br> printf("New name: ");
<br> gets(newname);
<br>
<br> /* Rename the file */
<br> if (rename(oldname, newname) == 0)
<br> printf("Renamed %s to %s.\n", oldname, newname);
<br> else
<br> perror("rename");
<br>
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: restorecrtmode
<br>功 能: 将屏幕模式恢复为先前的imitgraph设置
<br>用 法: void far restorecrtmode(void);
<br>程序例:
<br>
<br>#include <graphics.h>
<br>#include <stdlib.h>
<br>#include <stdio.h>
<br>#include <conio.h>
<br>
<br>int main(void)
<br>{
<br> /* request auto detection */
<br> int gdriver = DETECT, gmode, errorcode;
<br> int x, y;
<br>
<br> /* initialize graphics and local variables */
<br> initgraph(&gdriver, &gmode, "");
<br>
<br> /* read result of initialization */
<br> errorcode = graphresult();
<br> if (errorcode != grOk) /* an error occurred */
<br> {
<br> printf("Graphics error: %s\n", grapherrormsg(errorcode));
<br> printf("Press any key to halt:");
<br> getch();
<br> exit(1); /* terminate with an error code */
<br> }
<br>
<br> x = getmaxx() / 2;
<br> y = getmaxy() / 2;
<br>
<br> /* output a message */
<br> settextjustify(CENTER_TEXT, CENTER_TEXT);
<br> outtextxy(x, y, "Press any key to exit graphics:");
<br> getch();
<br>
<br> /* restore system to text mode */
<br> restorecrtmode();
<br> printf("We're now in text mode.\n");
<br> printf("Press any key to return to graphics mode:");
<br> getch();
<br>
<br> /* return to graphics mode */
<br> setgraphmode(getgraphmode());
<br>
<br> /* output a message */
<br> settextjustify(CENTER_TEXT, CENTER_TEXT);
<br> outtextxy(x, y, "We're back in graphics mode.");
<br> outtextxy(x, y+textheight("W"), "Press any key to halt:");
<br>
<br> /* clean up */
<br> getch();
<br> closegraph();
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: rewind
<br>功 能: 将文件指针重新指向一个流的开头
<br>用 法: int rewind(FILE *stream);
<br>程序例:
<br>
<br>#include <stdio.h>
<br>#include <dir.h>
<br>
<br> int main(void)
<br> {
<br> FILE *fp;
<br> char *fname = "TXXXXXX", *newname, first;
<br>
<br> newname = mktemp(fname);
<br> fp = fopen(newname,"w+");
<br> fprintf(fp,"abcdefghijklmnopqrstuvwxyz");
<br> rewind(fp);
<br> fscanf(fp,"%c",&first);
<br> printf("The first character is: %c\n",first);
<br> fclose(fp);
<br> remove(newname);
<br>
<br> return 0;
<br>}
<br>
<br>
<br>
<br>函数名: rmdir
<br>功 能: 删除DOS文件目录
<br>用 法: int rmdir(char *stream);
<br>程序例:
<br>
<br>#include <stdio.h>
<br>#include <conio.h>
<br>#include <process.h>
<br>#include <dir.h>
<br>
<br>#define DIRNAME "testdir.$$$"
<br>
<br>int main(void)
<br>{
<br> int stat;
<br>
<br> stat = mkdir(DIRNAME);
<br> if (!stat)
<br> printf("Directory created\n");
<br> else
<br> {
<br> printf("Unable to create directory\n");
<br> exit(1);
<br> }
<br>
<br> getch();
<br> system("dir/p");
<br> getch();
<br>
<br> stat = rmdir(DIRNAME);
<br> if (!stat)
<br> printf("\nDirectory deleted\n");
<br> else
<br> {
<br> perror("\nUnable to delete directory\n");
<br> exit(1);
<br> }
<br>
<br> return 0;
<br>}
<br>
<br>(<a href=http://www.fanqiang.com>http://www.fanqiang.com</a>)</font> 进入【<a href=http://www.chinaunix.net>UNIX论坛</a>】</td></tr><tr><td><hr></td></tr><tr><td><b>相关文章</b> </td></tr><tr><td><a href=/a4/b2/20011027/1305001515.html>C语言库函数(W类字母)</a> <small>(2001-10-27 13:05:00)</small></font><br><a href=/a4/b2/20011027/0905001514.html>C语言库函数(V类字母)</a> <small>(2001-10-27 09:05:00)</small></font><br><a href=/a4/b2/20011027/0805011513.html>C语言库函数(U类字母)</a> <small>(2001-10-27 08:05:01)</small></font><br><a href=/a4/b2/20011027/0705001512.html>C语言库函数(T类字母)</a> <small>(2001-10-27 07:05:00)</small></font><br><a href=/a4/b2/20011026/0900001511.html>C语言库函数(S类字母) - 3</a> <small>(2001-10-26 09:00:00)</small></font><br><a href=/a4/b2/20011026/0800011510.html>C语言库函数(S类字母) - 2</a> <small>(2001-10-26 08:00:01)</small></font><br><a href=/a4/b2/20011026/0700001509.html>C语言库函数(S类字母) - 1</a> <small>(2001-10-26 07:00:00)</small></font><br><a href=/a4/b2/20011025/0900011508.html>C语言库函数(R类字母)</a> <small>(2001-10-25 09:00:01)</small></font><br><a href=/a4/b2/20011025/0800031507.html>C语言库函数(Q类字母)</a> <small>(2001-10-25 08:00:03)</small></font><br><a href=/a4/b2/20011025/0700011506.html>C语言库函数(P类字母)</a> <small>(2001-10-25 07:00:01)</small></font><br></td></tr><tr><tr><td><br>===<a href=/cgi-bin/find.cgi?key=C语言库函数>更多相关</a>===</td></tr><td> </td></tr></table></td></tr><tr> <td width="100%" height="2" colspan="5" bgcolor="#D09F0D"><img src="/images/c.gif" width=1 height=1></td> </tr><tr> <td width="100%" height="40" colspan="5" valign=top><p align="center"><font color=#ffffff>★ 樊强制作 欢迎分享 ★ </font></p></td> </tr></table></center></div></body></html>⌨️ 快捷键说明
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