limits

标准库标头<limits>

此标头是类型支撑图书馆。

声明

numeric_limits	provides an interface to query properties of all fundamental numeric types. (class template)
float_round_style	indicates floating-point rounding modes (enum)
float_denorm_style	indicates floating-point denormalization modes (enum)

简介

二次

namespace std {
    template<class T> class numeric_limits;
 
    enum float_round_style {
        round_indeterminate         = -1,
        round_toward_zero           =  0,
        round_to_nearest            =  1,
        round_toward_infinity       =  2,
        round_toward_neg_infinity   =  3,
    };
 
    enum float_denorm_style {
        denorm_indeterminate = -1,
        denorm_absent        =  0,
        denorm_present       =  1
    };
 
 
    template<> class numeric_limits<bool>;
 
    template<> class numeric_limits<char>;
    template<> class numeric_limits<signed char>;
    template<> class numeric_limits<unsigned char>;
    template<> class numeric_limits<char16_t>;
    template<> class numeric_limits<char32_t>;
    template<> class numeric_limits<wchar_t>;
 
    template<> class numeric_limits<short>;
    template<> class numeric_limits<int>;
    template<> class numeric_limits<long>;
    template<> class numeric_limits<long long>;
    template<> class numeric_limits<unsigned short>;
    template<> class numeric_limits<unsigned int>;
    template<> class numeric_limits<unsigned long>;
    template<> class numeric_limits<unsigned long long>;
 
    template<> class numeric_limits<float>;
    template<> class numeric_limits<double>;
    template<> class numeric_limits<long double>;
}

二次

类模板std::numeric_limits

二次

template<class T> class numeric_limits {
public:
    static constexpr bool is_specialized = false;
 
    static constexpr T min() noexcept { return T( }
    static constexpr T max() noexcept { return T( }
    static constexpr T lowest() noexcept { return T( }
 
    static constexpr int digits = 0;
    static constexpr int digits10 = 0;
    static constexpr int max_digits10 = 0;
 
    static constexpr bool is_signed = false;
    static constexpr bool is_integer = false;
    static constexpr bool is_exact = false;
    static constexpr int radix = 0;
    static constexpr T epsilon() noexcept { return T( }
    static constexpr T round_error() noexcept { return T( }
 
    static constexpr int min_exponent = 0;
    static constexpr int min_exponent10 = 0;
    static constexpr int max_exponent = 0;
    static constexpr int max_exponent10 = 0;
 
    static constexpr bool has_infinity = false;
    static constexpr bool has_quiet_NaN = false;
    static constexpr bool has_signaling_NaN = false;
    static constexpr float_denorm_style has_denorm = denorm_absent;
    static constexpr bool has_denorm_loss = false;
    static constexpr T infinity() noexcept { return T( }
    static constexpr T quiet_NaN() noexcept { return T( }
    static constexpr T signaling_NaN() noexcept { return T( }
    static constexpr T denorm_min() noexcept { return T( }
 
    static constexpr bool is_iec559 = false;
    static constexpr bool is_bounded = false;
    static constexpr bool is_modulo = false;
 
    static constexpr bool traps = false;
    static constexpr bool tinyness_before = false;
    static constexpr float_round_style round_style = round_toward_zero;
 
};

二次

专业化std::numeric_limits<bool>

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template<> class numeric_limits<bool> {
public:
    static constexpr bool is_specialized = true;
 
    static constexpr bool min() noexcept { return false; }
    static constexpr bool max() noexcept { return true; }
    static constexpr bool lowest() noexcept { return false; }
 
    static constexpr int digits = 1;
    static constexpr int digits10 = 0;
    static constexpr int max_digits10 = 0;
 
    static constexpr bool is_signed = false;
    static constexpr bool is_integer = true;
    static constexpr bool is_exact = true;
    static constexpr int radix = 2;
    static constexpr bool epsilon() noexcept { return 0; }
    static constexpr bool round_error() noexcept { return 0; }
 
    static constexpr int min_exponent = 0;
    static constexpr int min_exponent10 = 0;
    static constexpr int max_exponent = 0;
    static constexpr int max_exponent10 = 0;
 
    static constexpr bool has_infinity = false;
    static constexpr bool has_quiet_NaN = false;
    static constexpr bool has_signaling_NaN = false;
    static constexpr float_denorm_style has_denorm = denorm_absent;
    static constexpr bool has_denorm_loss = false;
    static constexpr bool infinity() noexcept { return 0; }
    static constexpr bool quiet_NaN() noexcept { return 0; }
    static constexpr bool signaling_NaN() noexcept { return 0; }
    static constexpr bool denorm_min() noexcept { return 0; }
 
    static constexpr bool is_iec559 = false;
    static constexpr bool is_bounded = true;
    static constexpr bool is_modulo = false;
 
    static constexpr bool traps = false;
    static constexpr bool tinyness_before = false;
    static constexpr float_round_style round_style = round_toward_zero;
 
};

二次

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