Converts a double value to a formatted string.

#include <stdlib.h>

char *ftoa(double value, char *string, unsigned int iplaces, unsigned int fplaces);

Parameters

value

Value to convert.

string

Pointer to a character array where a null-terminated character string is written.

iplaces

Desired number of significant integer digits (iii) in the string.

fplaces

Desired number of significant fractional digits (fff) in the string. An integer exponent (eee) also returns in the string.

Remarks

The converted string has this format:

[-]iii.fffE[-]eee

The value of the number is truncated, not rounded. The algorithm that ftoa uses is accurate to eighteen significant digits. If iplaces plus fplaces exceeds eighteen, they are adjusted so that only eighteen significant digits are used.

For portability, use the sprintf %e conversion specifier. Use the optional field width and precision to control the number of fractional digits. The sprintf %e conversion specifier produces a string in the format [-]d.dddE+ee, with one integer digit left of the decimal point.

Return Values

A pointer to the converted string.

Requirements

See Also

sprintf