📄 025.htm
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<P>函数名: fgetchar
<BR>功 能: 从流中读取字符
<BR>用 法: int fgetchar(void);
<BR>程序例:
<BR>
<P>#include <stdio.h>
<BR>
<P>int main(void)
<BR>{
<BR> char ch;
<BR>
<P> /* prompt the user for input */
<BR> printf("Enter a character followed by \
<BR> <Enter>: ");
<BR>
<P> /* read the character from stdin */
<BR> ch = fgetchar();
<BR>
<P> /* display what was read */
<BR> printf("The character read is: '%c'\n",
<BR> ch);
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: fgetpos
<BR>功 能: 取得当前文件的句柄
<BR>用 法: int fgetpos(FILE *stream);
<BR>程序例:
<BR>
<P>#include <string.h>
<BR>#include <stdio.h>
<BR>
<P>int main(void)
<BR>{
<BR> FILE *stream;
<BR> char string[] = "This is a test";
<BR> fpos_t filepos;
<BR>
<P> /* open a file for update */
<BR> stream = fopen("DUMMY.FIL", "w+");
<BR>
<P> /* write a string into the file */
<BR> fwrite(string, strlen(string), 1, stream);
<BR>
<P> /* report the file pointer position */
<BR> fgetpos(stream, &filepos);
<BR> printf("The file pointer is at byte\
<BR> %ld\n", filepos);
<BR>
<P> fclose(stream);
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: fgets
<BR>功 能: 从流中读取一字符串
<BR>用 法: char *fgets(char *string, int n, FILE *stream);
<BR>程序例:
<BR>
<P>#include <string.h>
<BR>#include <stdio.h>
<BR>
<P>int main(void)
<BR>{
<BR> FILE *stream;
<BR> char string[] = "This is a test";
<BR> char msg[20];
<BR>
<P> /* open a file for update */
<BR> stream = fopen("DUMMY.FIL", "w+");
<BR>
<P> /* write a string into the file */
<BR> fwrite(string, strlen(string), 1, stream);
<BR>
<P> /* seek to the start of the file */
<BR> fseek(stream, 0, SEEK_SET);
<BR>
<P> /* read a string from the file */
<BR> fgets(msg, strlen(string)+1, stream);
<BR>
<P> /* display the string */
<BR> printf("%s", msg);
<BR>
<P> fclose(stream);
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: filelength
<BR>功 能: 取文件长度字节数
<BR>用 法: long filelength(int handle);
<BR>程序例:
<BR>
<P>#include <string.h>
<BR>#include <stdio.h>
<BR>#include <fcntl.h>
<BR>#include <io.h>
<BR>
<P>int main(void)
<BR>{
<BR> int handle;
<BR> char buf[11] = "0123456789";
<BR>
<P> /* create a file containing 10 bytes */
<BR> handle = open("DUMMY.FIL", O_CREAT);
<BR> write(handle, buf, strlen(buf));
<BR>
<P> /* display the size of the file */
<BR> printf("file length in bytes: %ld\n",
<BR> filelength(handle));
<BR>
<P> /* close the file */
<BR> close(handle);
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<P>函数名: fillellipse
<BR>功 能: 画出并填充一椭圆
<BR>用 法: void far fillellipse(int x, int y, int xradius, int yradius);
<BR>程序例:
<BR>
<P>#include <graphics.h>
<BR>#include <conio.h>
<BR>
<P>int main(void)
<BR>{
<BR> int gdriver = DETECT, gmode;
<BR> int xcenter, ycenter, i;
<BR>
<P> initgraph(&gdriver,&gmode,"");
<BR> xcenter = getmaxx() / 2;
<BR> ycenter = getmaxy() / 2;
<BR>
<P> for (i=0; i<13; i++)
<BR> {
<BR> setfillstyle(i,WHITE);
<BR> fillellipse(xcenter,ycenter,100,50);
<BR> getch();
<BR> }
<BR>
<P> closegraph();
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: fillpoly
<BR>功 能: 画并填充一个多边形
<BR>用 法: void far fillpoly(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 i, maxx, maxy;
<BR>
<P> /* our polygon array */
<BR> int poly[8];
<BR>
<P> /* initialize graphics, local 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> exit(1);
<BR> /* terminate with an error code */
<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> /*
<BR> 4th vertex. fillpoly automatically
<BR> closes the polygon.
<BR> */
<BR> poly[6] = maxx / 2;
<BR> poly[7] = maxy / 2;
<BR>
<P> /* loop through the fill patterns */
<BR> for (i=EMPTY_FILL; i<USER_FILL; i++)
<BR> {
<BR> /* set fill pattern */
<BR> setfillstyle(i, getmaxcolor());
<BR>
<P> /* draw a filled polygon */
<BR> fillpoly(4, poly);
<BR>
<P> getch();
<BR> }
<BR>
<P> /* clean up */
<BR> closegraph();
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: findfirst, findnext
<BR>功 能: 搜索磁盘目录; 取得下一个匹配的findfirst模式的文件
<BR>用 法: int findfirst(char *pathname, struct ffblk *ffblk, int
attrib);
<BR> int findnext(struct ffblk *ffblk);
<BR>程序例:
<BR>
<P>/* findnext example */
<BR>
<P>#include <stdio.h>
<BR>#include <dir.h>
<BR>
<P>int main(void)
<BR>{
<BR> struct ffblk ffblk;
<BR> int done;
<BR> printf("Directory listing of *.*\n");
<BR> done = findfirst("*.*",&ffblk,0);
<BR> while (!done)
<BR> {
<BR> printf(" %s\n", ffblk.ff_name);
<BR> done = findnext(&ffblk);
<BR> }
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: floodfill
<BR>功 能: 填充一个有界区域
<BR>用 法: void far floodfill(int x, int y, int border);
<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> /* initialize graphics, local 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> exit(1);
<BR> /* terminate with an error code */
<BR> }
<BR>
<P> maxx = getmaxx();
<BR> maxy = getmaxy();
<BR>
<P> /* select drawing color */
<BR> setcolor(getmaxcolor());
<BR>
<P> /* select fill color */
<BR> setfillstyle(SOLID_FILL, getmaxcolor());
<BR>
<P> /* draw a border around the screen */
<BR> rectangle(0, 0, maxx, maxy);
<BR>
<P> /* draw some circles */
<BR> circle(maxx / 3, maxy /2, 50);
<BR> circle(maxx / 2, 20, 100);
<BR> circle(maxx-20, maxy-50, 75);
<BR> circle(20, maxy-20, 25);
<BR>
<P> /* wait for a key */
<BR> getch();
<BR>
<P> /* fill in bounded region */
<BR> floodfill(2, 2, getmaxcolor());
<BR>
<P> /* clean up */
<BR> getch();
<BR> closegraph();
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: floor
<BR>功 能: 向下舍入
<BR>用 法: double floor(double x);
<BR>程序例:
<BR>
<P>#include <stdio.h>
<BR>#include <math.h>
<BR>
<P>int main(void)
<BR>{
<BR> double number = 123.54;
<BR> double down, up;
<BR>
<P> down = floor(number);
<BR> up = ceil(number);
<BR>
<P> printf("original number %10.2lf\n",
<BR> number);
<BR> printf("number rounded down %10.2lf\n",
<BR> down);
<BR> printf("number rounded up %10.2lf\n",
<BR> up);
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: flushall
<BR>功 能: 清除所有缓冲区
<BR>用 法: int flushall(void);
<BR>程序例:
<BR>
<P>#include <stdio.h>
<BR>
<P>int main(void)
<BR>{
<BR> FILE *stream;
<BR>
<P> /* create a file */
<BR> stream = fopen("DUMMY.FIL", "w");
<BR>
<P> /* flush all open streams */
<BR> printf("%d streams were flushed.\n",
<BR> flushall());
<BR>
<P> /* close the file */
<BR> fclose(stream);
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: fmod
<BR>功 能: 计算x对y的模, 即x/y的余数
<BR>用 法: double fmod(double x, double y);
<BR>程序例:
<BR>
<P>#include <stdio.h>
<BR>#include <math.h>
<BR>
<P>int main(void)
<BR>{
<BR> double x = 5.0, y = 2.0;
<BR> double result;
<BR>
<P> result = fmod(x,y);
<BR> printf("The remainder of (%lf / %lf) is \
<BR> %lf\n", x, y,
result);
<BR> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: fnmerge
<BR>功 能: 建立新文件名
<BR>用 法: void fnerge(char *path, char *drive, char *dir);
<BR>程序例:
<BR>
<P>#include <string.h>
<BR>#include <stdio.h>
<BR>#include <dir.h>
<BR>
<BR>
<P>int main(void)
<BR>{
<BR> char s[MAXPATH];
<BR> char drive[MAXDRIVE];
<BR> char dir[MAXDIR];
<BR> char file[MAXFILE];
<BR> char ext[MAXEXT];
<BR>
<P> getcwd(s,MAXPATH);
/* get the current working directory */
<BR> strcat(s,"\\");
/* append on a trailing \ character */
<BR> fnsplit(s,drive,dir,file,ext); /* split the string
to separate elems */
<BR> strcpy(file,"DATA");
<BR> strcpy(ext,".TXT");
<BR> fnmerge(s,drive,dir,file,ext); /* merge
everything into one string */
<BR> puts(s);
/* display resulting string */
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<BR>
<BR>
<P>函数名: fopen
<BR>功 能: 打开一个流
<BR>用 法: FILE *fopen(char *filename, char *type);
<BR>程序例:
<BR>
<P>#include <stdlib.h>
<BR>#include <stdio.h>
<BR>#include <dir.h>
<BR>
<P>int main(void)
<BR>{
<BR> char *s;
<BR> char drive[MAXDRIVE];
<BR> char dir[MAXDIR];
<BR> char file[MAXFILE];
<BR> char ext[MAXEXT];
<BR> int flags;
<BR>
<P> s=getenv("COMSPEC"); /* get the comspec environment
parameter */
<BR> flags=fnsplit(s,drive,dir,file,ext);
<BR>
<P> printf("Command processor info:\n");
<BR> if(flags & DRIVE)
<BR> printf("\tdrive: %s\n",drive);
<BR> if(flags & DIRECTORY)
<BR> printf("\tdirectory: %s\n",dir);
<BR> if(flags & FILENAME)
<BR> printf("\tfile: %s\n",file);
<BR> if(flags & EXTENSION)
<BR> printf("\textension: %s\n",ext);
<BR>
<P> return 0;
<BR>}
<BR>
<BR>
<P>函数名: fprintf
<BR>功 能: 传送格式化输出到一个流中
<BR>用 法: int fprintf(FILE *stream, char *format[, argument,...]);
<BR>程序例:
<BR>
<P>/* Program to create backup of the
<BR> AUTOEXEC.BAT file */
<BR>
<P>#include <stdio.h>
<BR>
<P>int main(void)
<BR>{
<BR> FILE *in, *out;
<BR>
<P> if ((in = fopen("\\AUTOEXEC.BAT", "rt"))
<BR> == NULL)
<BR> {
<BR> fprintf(stderr, "Cannot open input \
<BR> file.\n");
<BR> return 1;
<BR> }
<BR>
<P> if ((out = fopen("\\AUTOEXEC.BAK", "wt"))
<BR> == NULL)
<BR> {
<BR> fprintf(stderr, "Cannot open output
\
<BR> file.\n");
<BR> return 1;
<BR> }
<BR>
<P> while (!feof(in))
<BR> fputc(fgetc(in), out);
<BR>
<P> fclose(in);
<BR> fclose(out);
<BR> return 0;
<BR>}
<BR>
<BR>
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