fclose(stream); 
return 0; 
} 




函數名: filelength 
功 能: 取文件長度字節數 
用 法: long filelength(int handle); 
程序例: 

#include <string.h> 
#include <stdio.h> 
#include <fcntl.h> 
#include <io.h> 

int main(void) 
{ 
int handle; 
char buf[11] = "0123456789"; 

/* create a file containing 10 bytes */ 
handle = open("DUMMY.FIL", O_CREAT); 
write(handle, buf, strlen(buf)); 

/* display the size of the file */ 
printf("file length in bytes: %ld\n", 
filelength(handle)); 

/* close the file */ 
close(handle); 
return 0; 
} 



函數名: fillellipse 
功 能: 畫出并填充一橢圓 
用 法: void far fillellipse(int x, int y, int xradius, int yradius); 
程序例: 

#include <graphics.h> 
#include <conio.h> 

int main(void) 
{ 
int gdriver = DETECT, gmode; 
int xcenter, ycenter, i; 

initgraph(&gdriver,&gmode,""); 
xcenter = getmaxx() / 2; 
ycenter = getmaxy() / 2; 

for (i=0; i<13; i++) 
{ 
setfillstyle(i,WHITE); 
fillellipse(xcenter,ycenter,100,50); 
getch(); 
} 

closegraph(); 
return 0; 
} 
函數名: fillpoly 
功 能: 畫并填充一個多邊形 
用 法: void far fillpoly(int numpoints, int far *polypoints); 
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; 
int i, maxx, maxy; 

/* our polygon array */ 
int poly[8]; 

/* initialize graphics, 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(); 
maxy = getmaxy(); 

poly[0] = 20; /* 1st vertext */ 
poly[1] = maxy / 2; 

poly[2] = maxx - 20; /* 2nd */ 
poly[3] = 20; 

poly[4] = maxx - 50; /* 3rd */ 
poly[5] = maxy - 20; 

/* 
4th vertex. fillpoly automatically 
closes the polygon. 
*/ 
poly[6] = maxx / 2; 
poly[7] = maxy / 2; 

/* loop through the fill patterns */ 
for (i=EMPTY_FILL; i<USER_FILL; i++) 
{ 
/* set fill pattern */ 
setfillstyle(i, getmaxcolor()); 

/* draw a filled polygon */ 
fillpoly(4, poly); 

getch(); 
} 

/* clean up */ 
closegraph(); 
return 0; 
} 




函數名: findfirst, findnext 
功 能: 搜索磁盤目錄; 取得下一個匹配的findfirst模式的文件 
用 法: int findfirst(char *pathname, struct ffblk *ffblk, int attrib); 
int findnext(struct ffblk *ffblk); 
程序例: 

/* findnext example */ 

#include <stdio.h> 
#include <dir.h> 

int main(void) 
{ 
struct ffblk ffblk; 
int done; 
printf("Directory listing of *.*\n"); 
done = findfirst("*.*",&ffblk,0); 
while (!done) 
{ 
printf(" %s\n", ffblk.ff_name); 
done = findnext(&ffblk); 
} 

return 0; 
} 




函數名: floodfill 
功 能: 填充一個有界區域 
用 法: void far floodfill(int x, int y, int border); 
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; 
int maxx, maxy; 

/* initialize graphics, 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(); 
maxy = getmaxy(); 

/* select drawing color */ 
setcolor(getmaxcolor()); 

/* select fill color */ 
setfillstyle(SOLID_FILL, getmaxcolor()); 

/* draw a border around the screen */ 
rectangle(0, 0, maxx, maxy); 

/* draw some circles */ 
circle(maxx / 3, maxy /2, 50); 
circle(maxx / 2, 20, 100); 
circle(maxx-20, maxy-50, 75); 
circle(20, maxy-20, 25); 

/* wait for a key */ 
getch(); 

/* fill in bounded region */ 
floodfill(2, 2, getmaxcolor()); 

/* clean up */ 
getch(); 
closegraph(); 
return 0; 
} 




函數名: floor 
功 能: 向下舍入 
用 法: double floor(double x); 
程序例: 

#include <stdio.h> 
#include <math.h> 

int main(void) 
{ 
double number = 123.54; 
double down, up; 

down = floor(number); 
up = ceil(number); 

printf("original number %10.2lf\n", 
number); 
printf("number rounded down %10.2lf\n", 
down); 
printf("number rounded up %10.2lf\n", 
up); 

return 0; 
} 




函數名: flushall 
功 能: 清除所有緩沖區 
用 法: int flushall(void); 
程序例: 

#include <stdio.h> 

int main(void) 
{ 
FILE *stream; 

/* create a file */ 
stream = fopen("DUMMY.FIL", "w"); 

/* flush all open streams */ 
printf("%d streams were flushed.\n", 
flushall()); 

/* close the file */ 
fclose(stream); 
return 0; 
} 




函數名: fmod 
功 能: 計算x對y的模, 即x/y的余數 
用 法: double fmod(double x, double y); 
程序例: 

#include <stdio.h> 
#include <math.h> 

int main(void) 
{ 
double x = 5.0, y = 2.0; 
double result; 

result = fmod(x,y); 
printf("The remainder of (%lf / %lf) is \ 
%lf\n", x, y, result); 
return 0; 
} 




函數名: fnmerge 
功 能: 建立新文件名 
用 法: void fnerge(char *path, char *drive, char *dir); 
程序例: 

#include <string.h> 
#include <stdio.h> 
#include <dir.h> 


int main(void) 
{ 
char s[MAXPATH]; 
char drive[MAXDRIVE]; 
char dir[MAXDIR]; 
char file[MAXFILE]; 
char ext[MAXEXT]; 

getcwd(s,MAXPATH); /* get the current working directory */ 
strcat(s,"\\"); /* append on a trailing \ character */ 
fnsplit(s,drive,dir,file,ext); /* split the string to separate elems */ 
strcpy(file,"DATA"); 
strcpy(ext,".TXT"); 
fnmerge(s,drive,dir,file,ext); /* merge everything into one string */ 
puts(s); /* display resulting string */ 

return 0; 
} 




函數名: fopen 
功 能: 打開一個流 
用 法: FILE *fopen(char *filename, char *type); 
程序例: 

#include <stdlib.h> 
#include <stdio.h> 
#include <dir.h> 

int main(void) 
{ 
char *s; 
char drive[MAXDRIVE]; 
char dir[MAXDIR]; 
char file[MAXFILE]; 
char ext[MAXEXT]; 
int flags; 

s=getenv("COMSPEC"); /* get the comspec environment parameter */ 
flags=fnsplit(s,drive,dir,file,ext); 

printf("Command processor info:\n"); 
if(flags & DRIVE) 
printf("\tdrive: %s\n",drive); 
if(flags & DIRECTORY) 
printf("\tdirectory: %s\n",dir); 
if(flags & FILENAME) 
printf("\tfile: %s\n",file); 
if(flags & EXTENSION) 
printf("\textension: %s\n",ext); 

return 0; 
} 


函數名: fprintf 
功 能: 傳送格式化輸出到一個流中 
用 法: int fprintf(FILE *stream, char *format[, argument,...]); 
程序例: 

/* Program to create backup of the 
AUTOEXEC.BAT file */ 

#include <stdio.h> 

int main(void) 
{ 
FILE *in, *out; 

if ((in = fopen("\\AUTOEXEC.BAT", "rt")) 
== NULL) 
{ 
fprintf(stderr, "Cannot open input \ 
file.\n"); 
return 1; 
} 

if ((out = fopen("\\AUTOEXEC.BAK", "wt")) 
== NULL) 
{ 
fprintf(stderr, "Cannot open output \ 
file.\n"); 
return 1; 
} 

while (!feof(in)) 
fputc(fgetc(in), out); 

fclose(in); 
fclose(out); 
return 0; 
} 




函數名: FP_OFF 
功 能: 獲取遠地址偏移量 
用 法: unsigned FP_OFF(void far *farptr); 
程序例: 

/* FP_OFF */ 

#include <dos.h> 
#include <stdio.h> 

int main(void) 
{ 
char *str = "fpoff.c"; 

printf("The offset of this file in memory\ 
is: %Fp\n", FP_OFF(str)); 

return 0; 
} 



函數名: FP_SEG 
功 能: 獲取遠地址段值 
用 法: unsigned FP_SEG(void far *farptr); 
程序例: 

/* FP_SEG */ 

#include <dos.h> 
#include <stdio.h> 

int main(void) 
{ 
char *filename = "fpseg.c"; 

printf("The offset of this file in memory\ 
is: %Fp\n", FP_SEG(filename)); 

return(0); 
} 




函數名: fputc 
功 能: 送一個字符到一個流中 
用 法: int fputc(int ch, FILE *stream); 
程序例: 

#include <stdio.h> 

int main(void) 
{ 
char msg[] = "Hello world"; 
int i = 0; 

while (msg[i]) 
{ 
fputc(msg[i], stdout); 
i++; 
} 
return 0; 
} 




函數名: fputchar 
功 能: 送一個字符到標準輸出流(stdout)中 
用 法: int fputchar(char ch); 
程序例: 

#include <stdio.h> 

int main(void) 
{ 
char msg[] = "This is a test"; 
int i = 0; 

while (msg[i]) 
{ 
fputchar(msg[i]); 
i++; 
} 
return 0; 
} 




函數名: fputs 
功 能: 送一個字符到一個流中 
用 法: int fputs(char *string, FILE *stream); 
程序例: 

#include <stdio.h> 

int main(void) 
{ 
/* write a string to standard output */ 
fputs("Hello world\n", stdout); 

return 0; 
} 




函數名: fread 
功 能: 從一個流中讀數據 
用 法: int fread(void *ptr, int size, int nitems, FILE *stream); 
程序例: 

#include <string.h> 
#include <stdio.h> 

int main(void) 
{ 
FILE *stream; 
char msg[] = "this is a test"; 
char buf[20]; 

if ((stream = fopen("DUMMY.FIL", "w+")) 
== NULL) 
{ 
fprintf(stderr, 
"Cannot open output file.\n"); 
return 1; 
} 

/* write some data to the file */ 
fwrite(msg, strlen(msg)+1, 1, stream); 

/* seek to the beginning of the file */ 
fseek(stream, SEEK_SET, 0); 

/* read the data and display it */ 
fread(buf, strlen(msg)+1, 1, stream); 
printf("%s\n", buf); 

fclose(stream); 
return 0; 
} 



函數名: free 
功 能: 釋放已分配的塊 
用 法: void free(void *ptr); 
程序例: 

#include <string.h> 
#include <stdio.h> 
#include <alloc.h> 

int main(void) 
{ 
char *str; 

/* allocate memory for string */ 
str = malloc(10); 

/* copy "Hello" to string */ 
strcpy(str, "Hello"); 

/* display string */ 
printf("String is %s\n", str); 

/* free memory */ 
free(str); 

return 0; 
} 


函數名: freemem 
功 能: 釋放先前分配的DOS內存塊 
用 法: int freemem(unsigned seg); 
程序例: 

#include <dos.h> 
#include <alloc.h> 
#include <stdio.h> 

int main(void) 
{ 
unsigned int size, segp; 
int stat; 

size = 64; /* (64 x 16) = 1024 bytes */ 
stat = allocmem(size, &segp); 
if (stat < 0) 
printf("Allocated memory at segment:\ 
%x\n", segp); 
else 
printf("Failed: maximum number of\ 
paragraphs available is %u\n", 
stat); 
freemem(segp); 

return 0; 
} 



函數名: freopen 
功 能: 替換一個流 
用 法: FILE *freopen(char *filename, char *type, FILE *stream); 
程序例: 

#include <stdio.h> 

int main(void) 
{ 
/* redirect standard output to a file */ 
if (freopen("OUTPUT.FIL", "w", stdout) 
== NULL) 
fprintf(stderr, "error redirecting\ 
stdout\n"); 

/* this output will go to a file */ 
printf("This will go into a file."); 

/* close the standard output stream */ 
fclose(stdout); 

return 0; 
} 




函數名: frexp 
功 能: 把一個雙精度數分解為尾數的指數 
用 法: double frexp(double value, int *eptr); 
程序例: 

#include <math.h> 
#include <stdio.h> 

int main(void) 
{ 
double mantissa, number; 
int exponent; 

number = 8.0; 
mantissa = frexp(number, &exponent); 

printf("The number %lf is ", number); 
printf("%lf times two to the ", mantissa); 
printf("power of %d\n", exponent); 

return 0; 
} 



函數名: fscanf 
功 能: 從一個流中執行格式化輸入 
用 法: int fscanf(FILE *stream, char *format[,argument...]); 
程序例: 

#include <stdlib.h> 
#include <stdio.h> 

int main(void) 
{ 
int i; 

printf("Input an integer: "); 

/* read an integer from the 
standard input stream */ 
if (fscanf(stdin, "%d", &i)) 
printf("The integer read was: %i\n", 
i); 
else 
{ 
fprintf(stderr, "Error reading an \ 
integer from stdin.\n"); 
exit(1); 
} 
return 0; 
} 




函數名: fseek 
功 能: 重定位流上的文件指針 
用 法: int fseek(FILE *stream, long offset, int fromwhere); 
程序例: 

#include <stdio.h> 

long filesize(FILE *stream); 

int main(void) 
{ 
FILE *stream; 

stream = fopen("MYFILE.TXT", "w+"); 
fprintf(stream, "This is a test"); 
printf("Filesize of MYFILE.TXT is %ld bytes\n", filesize(stream)); 
fclose(stream); 
return 0; 
} 

long filesize(FILE *stream) 
{ 
long curpos, length; 

curpos = ftell(stream); 
fseek(stream, 0L, SEEK_END); 
length = ftell(stream); 
fseek(stream, curpos, SEEK_SET); 
return length; 
} 






函數名: fsetpos 
功 能: 定位流上的文件指針 
用 法: int fsetpos(FILE *stream, const fpos_t *pos); 
程序例: 

#include <stdlib.h> 
#include <stdio.h> 

void showpos(FILE *stream); 

int main(void) 
{ 
FILE *stream; 
fpos_t filepos; 

/* open a file for update */ 
stream = fopen("DUMMY.FIL", "w+"); 

/* save the file pointer position */ 
fgetpos(stream, &filepos); 

/* write some data to the file */ 
fprintf(stream,