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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision b32248757d988141073a4bfc0f72544e9f6a5e22 authored by Benjamin Peterson on 29 June 2010, 15:18:02 UTC, committed by Benjamin Peterson on 29 June 2010, 15:18:02 UTC 
group cStringIO docs under its factory function
1 parent 86aa905
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Tip revision: b32248757d988141073a4bfc0f72544e9f6a5e22 authored by Benjamin Peterson on 29 June 2010, 15:18:02 UTC
group cStringIO docs under its factory function
Tip revision: b322487
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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