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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision ca1512cd83b29257023797c21acc55ccef34253c authored by Anthony Baxter on 10 January 2002, 11:10:18 UTC, committed by Anthony Baxter on 10 January 2002, 11:10:18 UTC 
thread_pthread.h
1 parent 9fd582b
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Tip revision: ca1512cd83b29257023797c21acc55ccef34253c authored by Anthony Baxter on 10 January 2002, 11:10:18 UTC
thread_pthread.h
Tip revision: ca1512c
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;
}
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