Skip to main content

Browse the archive

Staging
v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision a5a38c508ee42a66ac57443ec3377cee405e6039 authored by Barry Warsaw on 02 October 2008, 03:08:34 UTC, committed by Barry Warsaw on 02 October 2008, 03:08:34 UTC 
Post release dance
1 parent f482bbd
Raw File
Tip revision: a5a38c508ee42a66ac57443ec3377cee405e6039 authored by Barry Warsaw on 02 October 2008, 03:08:34 UTC
Post release dance
Tip revision: a5a38c5
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 "pyconfig.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