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C语言库函数(F类字母)
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C语言库函数(F类字母)
http://www.pptel.net/content/view/464/56/
作者: haixiao ouyang          
 
2005-09-23 
 

函数名: fabs
功 能: 返回浮点数的绝对值
用 法: double fabs(double x);
程序例:
#include <stdio.h>
#include <math.h>

int main(void)
{
float number = -1234.0;

printf("number: %f absolute value: %f\n",
number, fabs(number));
return 0;
}

 


函数名: farcalloc
功 能: 从远堆栈中申请空间
用 法: void far *farcalloc(unsigned long units, unsigned ling unitsz);
程序例:
#include <stdio.h>
#include <alloc.h>
#include <string.h>
#include <dos.h>

int main(void)
{
char far *fptr;
char *str = "Hello";

/* allocate memory for the far pointer */
fptr = farcalloc(10, sizeof(char));

/* copy "Hello" into allocated memory */
/*
Note: movedata is used because you
might be in a small data model, in
which case a normal string copy routine
can not be used since it assumes the
pointer size is near.
*/
movedata(FP_SEG(str), FP_OFF(str),
FP_SEG(fptr), FP_OFF(fptr),
strlen(str));

/* display string (note the F modifier) */
printf("Far string is: %Fs\n", fptr);

/* free the memory */
farfree(fptr);

return 0;
}

 


函数名: farcoreleft
功 能: 返回远堆中未作用存储区大小
用 法: long farcoreleft(void);
程序例:

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

int main(void)
{
printf("The difference between the\
highest allocated block in the\
far\n");
printf("heap and the top of the far heap\
is: %lu bytes\n", farcoreleft());

return 0;
}

 


函数名: farfree
功 能: 从远堆中释放一块
用 法: void farfree(void);
程序例:

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

int main(void)
{
char far *fptr;
char *str = "Hello";

/* allocate memory for the far pointer */
fptr = farcalloc(10, sizeof(char));

/* copy "Hello" into allocated memory */
/*
Note: movedata is used because you might be in a small data model,
in which case a normal string copy routine can't be used since it
assumes the pointer size is near.
*/
movedata(FP_SEG(str), FP_OFF(str),
FP_SEG(fptr), FP_OFF(fptr),
strlen(str));

/* display string (note the F modifier) */
printf("Far string is: %Fs\n", fptr);

/* free the memory */
farfree(fptr);

return 0;
}

 


函数名: farmalloc
功 能: 从远堆中分配存储块
用 法: void far *farmalloc(unsigned long size);
程序例:

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

int main(void)
{
char far *fptr;
char *str = "Hello";

/* allocate memory for the far pointer */
fptr = farmalloc(10);

/* copy "Hello" into allocated memory */
/*
Note: movedata is used because we might
be in a small data model, in which case
a normal string copy routine can not be
used since it assumes the pointer size
is near.
*/
movedata(FP_SEG(str), FP_OFF(str),
FP_SEG(fptr), FP_OFF(fptr),
strlen(str));

/* display string (note the F modifier) */
printf("Far string is: %Fs\n", fptr);

/* free the memory */
farfree(fptr);

return 0;
}

 


函数名: farrealloc
功 能: 调整远堆中的分配块
用 法: void far *farrealloc(void far *block, unsigned long newsize);
程序例:

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

int main(void)
{
char far *fptr;

fptr = farmalloc(10);
printf("First address: %Fp\n", fptr);
fptr = farrealloc(fptr,20);
printf("New address : %Fp\n", fptr);
farfree(fptr);
return 0;
}

 

函数名: fclose
功 能: 关闭一个流
用 法: int fclose(FILE *stream);
程序例:

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

int main(void)
{
FILE *fp;
char buf[11] = "0123456789";

/* create a file containing 10 bytes */
fp = fopen("DUMMY.FIL", "w");
fwrite(&buf, strlen(buf), 1, fp);

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

 


函数名: fcloseall
功 能: 关闭打开流
用 法: int fcloseall(void);
程序例:

#include <stdio.h>

int main(void)
{
int streams_closed;

/* open two streams */
fopen("DUMMY.ONE", "w");
fopen("DUMMY.TWO", "w");

/* close the open streams */
streams_closed = fcloseall();

if (streams_closed == EOF)
/* issue an error message */
perror("Error");
else
/* print result of fcloseall() function */
printf("%d streams were closed.\n", streams_closed);

return 0;
}

 

函数名: fcvt
功 能: 把一个浮点数转换为字符串
用 法: char *fcvt(double value, int ndigit, int *decpt, int *sign);
程序例:

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

int main(void)
{
char *string;
double value;
int dec, sign;
int ndig = 10;

clrscr();
value = 9.876;
string = ecvt(value, ndig, &dec, &sign);
printf("string = %s dec = %d \
sign = %d\n", string, dec, sign);

value = -123.45;
ndig= 15;
string = ecvt(value,ndig,&dec,&sign);
printf("string = %s dec = %d sign = %d\n",
string, dec, sign);


value = 0.6789e5; /* scientific
notation */
ndig = 5;
string = ecvt(value,ndig,&dec,&sign);
printf("string = %s dec = %d\
sign = %d\n", string, dec, sign);

return 0;
}

 


函数名: fdopen
功 能: 把流与一个文件句柄相接
用 法: FILE *fdopen(int handle, char *type);
程序例:

#include <sys\stat.h>
#include <stdio.h>
#include <fcntl.h>
#include <io.h>

int main(void)
{
int handle;
FILE *stream;

/* open a file */
handle = open("DUMMY.FIL", O_CREAT,
S_IREAD | S_IWRITE);

/* now turn the handle into a stream */
stream = fdopen(handle, "w");

if (stream == NULL)
printf("fdopen failed\n");
else
{
fprintf(stream, "Hello world\n");
fclose(stream);
}
return 0;
}

 

函数名: feof
功 能: 检测流上的文件结束符
用 法: int feof(FILE *stream);
程序例:

#include <stdio.h>

int main(void)
{
FILE *stream;

/* open a file for reading */
stream = fopen("DUMMY.FIL", "r");

/* read a character from the file */
fgetc(stream);

/* check for EOF */
if (feof(stream))
printf("We have reached end-of-file\n");

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

 

函数名: ferror
功 能: 检测流上的错误
用 法: int ferror(FILE *stream);
程序例:

#include <stdio.h>

int main(void)
{
FILE *stream;

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

/* force an error condition by attempting to read */
(void) getc(stream);

if (ferror(stream)) /* test for an error on the stream */
{
/* display an error message */
printf("Error reading from DUMMY.FIL\n");

/* reset the error and EOF indicators */
clearerr(stream);
}

fclose(stream);
return 0;
}

 


函数名: fflush
功 能: 清除一个流
用 法: int fflush(FILE *stream);
程序例:

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

void flush(FILE *stream);

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

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

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

clrscr();
printf("Press any key to flush\
DUMMY.FIL:");
getch();

/* flush the data to DUMMY.FIL without\
closing it */
flush(stream);

printf("\nFile was flushed, Press any key\
to quit:");
getch();
return 0;
}

void flush(FILE *stream)
{
int duphandle;

/* flush the stream's internal buffer */
fflush(stream);

/* make a duplicate file handle */
duphandle = dup(fileno(stream));

/* close the duplicate handle to flush\
the DOS buffer */
close(duphandle);
}

 


函数名: fgetc
功 能: 从流中读取字符
用 法: int fgetc(FILE *stream);
程序例:

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

int main(void)
{
FILE *stream;
char string[] = "This is a test";
char ch;

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

/* write a string into the file */
fwrite(string, strlen(string), 1, stream);

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

do
{
/* read a char from the file */
ch = fgetc(stream);

/* display the character */
putch(ch);
} while (ch != EOF);

fclose(stream);
return 0;
}

 


函数名: fgetchar
功 能: 从流中读取字符
用 法: int fgetchar(void);
程序例:

#include <stdio.h>

int main(void)
{
char ch;

/* prompt the user for input */
printf("Enter a character followed by \
<Enter>: ");

/* read the character from stdin */
ch = fgetchar();

/* display what was read */
printf("The character read is: '%c'\n",
ch);
return 0;
}

 


函数名: fgetpos
功 能: 取得当前文件的句柄
用 法: int fgetpos(FILE *stream);
程序例:

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

int main(void)
{
FILE *stream;
char string[] = "This is a test";
fpos_t filepos;

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

/* write a string into the file */
fwrite(string, strlen(string), 1, stream);

/* report the file pointer position */
fgetpos(stream, &filepos);
printf("The file pointer is at byte\
%ld\n", filepos);

fclose(stream);
return 0;
}

 


函数名: fgets
功 能: 从流中读取一字符串
用 法: char *fgets(char *string, int n, FILE *stream);
程序例:

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

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

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

/* write a string into the file */
fwrite(string, strlen(string), 1, stream);

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

/* read a string from the file */
fgets(msg, strlen(string)+1, stream);

/* display the string */
printf("%s", msg);

fclose(stream);
return 0;
}

 


函数名: filelength
功 能: 取文件长度字节数
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;
}

 

函数名: fillellipse
功 能: 画出并填充一椭圆
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;
}
函数名: fillpoly
功 能: 画并填充一个多边形
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;
}

 


函数名: findfirst, findnext
功 能: 搜索磁盘目录; 取得下一个匹配的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;
}

 


函数名: floodfill
功 能: 填充一个有界区域
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;
}

 


函数名: 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;
}

 


函数名: flushall
功 能: 清除所有缓冲区
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;
}

 


函数名: fmod
功 能: 计算x对y的模, 即x/y的余数
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;
}

 


函数名: 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;
}

 


函数名: fopen
功 能: 打开一个流
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;
}


函数名: fprintf
功 能: 传送格式化输出到一个流中
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;
}

 


函数名: FP_OFF
功 能: 获取远地址偏移量
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;
}

 

函数名: FP_SEG
功 能: 获取远地址段值
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);
}

 


函数名: fputc
功 能: 送一个字符到一个流中
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;
}

 


函数名: fputchar
功 能: 送一个字符到标准输出流(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;
}

 


函数名: fputs
功 能: 送一个字符到一个流中
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;
}

 


函数名: fread
功 能: 从一个流中读数据
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;
}

 

函数名: free
功 能: 释放已分配的块
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;
}


函数名: freemem
功 能: 释放先前分配的DOS内存块
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;
}

 

函数名: freopen
功 能: 替换一个流
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;
}

 


函数名: frexp
功 能: 把一个双精度数分解为尾数的指数
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;
}

 

函数名: fscanf
功 能: 从一个流中执行格式化输入
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;
}

 


函数名: fseek
功 能: 重定位流上的文件指针
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;
}

 

 


函数名: fsetpos
功 能: 定位流上的文件指针
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, "This is a test");

/* show the current file position */
showpos(stream);

/* set a new file position, display it */
if (fsetpos(stream, &filepos) == 0)
showpos(stream);
else
{
fprintf(stderr, "Error setting file \
pointer.\n");
exit(1);
}

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

void showpos(FILE *stream)
{
fpos_t pos;

/* display the current file pointer
position of a stream */
fgetpos(stream, &pos);
printf("File position: %ld\n", pos);
}


函数名: fstat
功 能: 获取打开文件信息
用 法: int fstat(char *handle, struct stat *buff);
程序例:

#include <sys\stat.h>
#include <stdio.h>
#include <time.h>

int main(void)
{
struct stat statbuf;
FILE *stream;

/* open a file for update */
if ((stream = fopen("DUMMY.FIL", "w+"))
== NULL)
{
fprintf(stderr, "Cannot open output \
file.\n");
return(1);
}
fprintf(stream, "This is a test");
fflush(stream);

/* get information about the file */
fstat(fileno(stream), &statbuf);
fclose(stream);

/* display the information returned */
if (statbuf.st_mode & S_IFCHR)
printf("Handle refers to a device.\n");
if (statbuf.st_mode & S_IFREG)
printf("Handle refers to an ordinary \
file.\n");
if (statbuf.st_mode & S_IREAD)
printf("User has read permission on \
file.\n");
if (statbuf.st_mode & S_IWRITE)
printf("User has write permission on \
file.\n");

printf("Drive letter of file: %c\n",
'A'+statbuf.st_dev);
printf("Size of file in bytes: %ld\n",
statbuf.st_size);
printf("Time file last opened: %s\n",
ctime(&statbuf.st_ctime));
return 0;
}

 


函数名: ftell
功 能: 返回当前文件指针
用 法: long ftell(FILE *stream);
程序例:

#include <stdio.h>

int main(void)
{
FILE *stream;

stream = fopen("MYFILE.TXT", "w+");
fprintf(stream, "This is a test");
printf("The file pointer is at byte \
%ld\n", ftell(stream));
fclose(stream);
return 0;
}

 


函数名: fwrite
功 能: 写内容到流中
用 法: int fwrite(void *ptr, int size, int nitems, FILE *stream);
程序例:

#include <stdio.h>

struct mystruct
{
int i;
char ch;
};

int main(void)
{
FILE *stream;
struct mystruct s;

if ((stream = fopen("TEST.$$$", "wb")) == NULL) /* open file TEST.$$$ */
{
fprintf(stderr, "Cannot open output file.\n");
return 1;
}
s.i = 0;
s.ch = 'A';
fwrite(&s, sizeof(s), 1, stream); /* write struct s to file */
fclose(stream); /* close file */
return 0;
}


 

 

<< pragma指令简介 / C/C++语言误区一 —— vo... >>

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