C语言函数大全F
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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
#include
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
#include
#include
#include
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
#include
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
#include #include
#include
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
#include
#include
#include
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
#include
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
#include
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
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
#include
#include
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",
