ecvt

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Header File

stdlib.h

Category

Conversion Routines, Math Routines

Prototype

char *ecvt(double value, int ndig, int *dec, int *sign);

Description

Converts a floating-point number to a string.

ecvt converts value to a null-terminated string of ndig digits, starting with the leftmost significant digit, and returns a pointer to the string. The position of the decimal point relative to the beginning of the string is stored indirectly through dec (a negative value for dec means that the decimal lies to the left of the returned digits). There is no decimal point in the string itself. If the sign of value is negative, the word pointed to by sign is nonzero; otherwise, it's 0. The low-order digit is rounded.

Return Value

The return value of ecvt points to static data for the string of digits whose content is overwritten by each call to ecvt and fcvt.

Example

#include <stdlib.h>
#include <stdio.h>
int main(void)
{
   char *string;
   double value;
   int dec, sign;
   int ndig = 10;
   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;
}

Portability

POSIX	Win32	ANSI C	ANSI C++
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