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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision a7077c865d76afe0bc9640ec0b8f2aa6c0df6f4b authored by Barry Warsaw on 16 August 2010, 22:58:18 UTC, committed by Barry Warsaw on 16 August 2010, 22:58:18 UTC 
Move NEWS file entry.
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Tip revision: a7077c865d76afe0bc9640ec0b8f2aa6c0df6f4b authored by Barry Warsaw on 16 August 2010, 22:58:18 UTC
Move NEWS file entry.
Tip revision: a7077c8
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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