Function strtod

src/fl/stl/cstdlib.cpp.hpp:238–321

}

double strtod(const char* str, char** endptr) {
    if (!str) {
        if (endptr) {
            *endptr = const_cast<char*>(str);
        }
        return 0.0;
    }

    const char* p = str;
    double result = 0.0;
    bool negative = false;

    // Skip leading whitespace
    while (*p == ' ' || *p == '\t' || *p == '\n' || *p == '\r' || *p == '\f' || *p == '\v') {
        p++;
    }

    // Handle sign
    if (*p == '-') {
        negative = true;
        p++;
    } else if (*p == '+') {
        p++;
    }

    const char* start = p;

    // Parse integer part
    while (*p >= '0' && *p <= '9') {
        result = result * 10.0 + (*p - '0');
        p++;
    }

    // Parse fractional part
    if (*p == '.') {
        p++;
        double fraction = 0.1;
        while (*p >= '0' && *p <= '9') {
            result += (*p - '0') * fraction;
            fraction *= 0.1;
            p++;
        }
    }

    // Parse exponent
    if (*p == 'e' || *p == 'E') {
        p++;
        bool expNegative = false;
        if (*p == '-') {
            expNegative = true;
            p++;
        } else if (*p == '+') {
            p++;
        }

        int exp = 0;
        while (*p >= '0' && *p <= '9') {
            exp = exp * 10 + (*p - '0');