ftoa

ftoa.c

void ftoa(double f, char *output)
{
    int m = log10(f);
    int digit;
    double precision = .0001;
    
    while (f > 0 + precision)
    {
        double weight = pow(10.0, m);
        digit = floor(f / weight);
        f -= (digit * weight);
        *(output++)= '0' + digit;
        if (m == 0)
            *(output++) = '.';
        m--;
    }
    *(output) = '\0';
}