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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision 1803024c8a13c14d1f02e640ddca054077449698 authored by Barry Warsaw on 01 March 2010, 22:16:51 UTC, committed by Barry Warsaw on 01 March 2010, 22:16:51 UTC 
More copyright year updates.
1 parent fc79e8f
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Tip revision: 1803024c8a13c14d1f02e640ddca054077449698 authored by Barry Warsaw on 01 March 2010, 22:16:51 UTC
More copyright year updates.
Tip revision: 1803024
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;
}
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