strtod

Summary

#include <stdlib.h>

float strtod (
  char *string,   /* string to convert */
  char **ptr);    /* ptr to subsequent characters */

Description

The strtod function converts string into a floating-point value. The input string is a sequence of characters that can be interpreted as a floating-point number. Whitespace characters at the beginning of string are skipped.

The value of *ptr is set to point to the first character in string immediately following the converted part of string. If ptr is NULL, no value is assigned to *ptr. If no conversion is possible, *ptr is set to the value of string and the value 0 is returned by the strtod function.

The strtod function requires string to have the following format:

〚{+|-}〛 digits 〚.digits〛 〚{e|E} 〚{+|-}〛 digits〛

Where

digits

May be one or more decimal digits (0-9).

Return Value

The strtod function returns the floating-point value that is produced by interpreting the characters in the string as a floating-point number.

Example

#include <stdlib.h>
#include <stdio.h> /* for printf */

void tst_strtod (void) {
  float f;
  char s [] = "1.23 other";
  char *p;

  f = strtod (s, &p);
  printf ("strtod(%s) = %f\n", s, f);

/* p points to " other" */
}