Skip to main content

Browse the archive

Staging
v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision e764968649152c10c9a8b159cefd608428aff469 authored by Fred Drake on 14 October 2000, 05:44:32 UTC, committed by Fred Drake on 14 October 2000, 05:44:32 UTC 
Update dependencies for the Macintosh manual.
1 parent c25296a
Raw File
Tip revision: e764968649152c10c9a8b159cefd608428aff469 authored by Fred Drake on 14 October 2000, 05:44:32 UTC
Update dependencies for the Macintosh manual.
Tip revision: e764968
atof.c 

/* Just in case you haven't got an atof() around...
   This one doesn't check for bad syntax or overflow,
   and is slow and inaccurate.
   But it's good enough for the occasional string literal... */

#include "config.h"

#include <ctype.h>

double atof(char *s)
{
	double a = 0.0;
	int e = 0;
	int c;
	while ((c = *s++) != '\0' && isdigit(c)) {
		a = a*10.0 + (c - '0');
	}
	if (c == '.') {
		while ((c = *s++) != '\0' && isdigit(c)) {
			a = a*10.0 + (c - '0');
			e = e-1;
		}
	}
	if (c == 'e' || c == 'E') {
		int sign = 1;
		int i = 0;
		c = *s++;
		if (c == '+')
			c = *s++;
		else if (c == '-') {
			c = *s++;
			sign = -1;
		}
		while (isdigit(c)) {
			i = i*10 + (c - '0');
			c = *s++;
		}
		e += i*sign;
	}
	while (e > 0) {
		a *= 10.0;
		e--;
	}
	while (e < 0) {
		a *= 0.1;
		e++;
	}
	return a;
}
back to top