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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision 1c88e0f52cfa6e7c9fca6da94946eff3f34f6daf authored by Georg Brandl on 30 March 2008, 19:41:39 UTC, committed by Georg Brandl on 30 March 2008, 19:41:39 UTC 
The other download formats will be available for 2.6 too.
1 parent 9d0b604
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Tip revision: 1c88e0f52cfa6e7c9fca6da94946eff3f34f6daf authored by Georg Brandl on 30 March 2008, 19:41:39 UTC
The other download formats will be available for 2.6 too.
Tip revision: 1c88e0f
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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