Members of the numeric_limits Class

Veranschaulicht, wie die Member der numeric_limits-Klasse in Visual C++ verwendet.

Um einen der Member dieser Klasse zu verweisen, müssen Sie den Typ dass Sie Informationen abrufen möchten, und den Membernamen angeben.Die Rückgabe ist entweder der Wert 1 für true oder 0 für false.Zum Beispiel numeric_limits<int::>Minute gibt den minimalen Wert für intzurück.

HinweisHinweis

Einige Member sind nur für bestimmte Typen gültig. finden Sie in der Onlinehilfe auf, um zu ermitteln, ob ein Member nur für einen bestimmten Typ gültig ist.

Beispiel

// Numeric.cpp
// compile with: /EHsc
//
// Variables and Functions:
//
//    has_denorm
//    has_denorm_loss
//    has_infinity
//    has_quiet_NaN
//    has_signaling_NaN
//    is_bounded
//    is_exact
//    is_iec559
//    is_integer
//    is_modulo
//    is_signed
//    is_specialized
//    tinyness_before
//    traps
//    round_style
//    digits
//    digits10
//    max_exponent
//    max_exponent10
//    min_exponent
//    min_exponent10
//    radix;
//    denorm_min()
//    epsilon()
//    infinity()
//    max()
//    min()
//    quiet_ NaN()
//    round_error()
//    signaling_NaN()
//////////////////////////////////////////////////////////////////////

#include <iostream>
#include <limits>

using namespace std;

int main() {
    cout << " 1 The minimum value for char is " <<
        (int)numeric_limits<char>::min() << endl;
    cout << " 2 The minimum value for int is  " <<
        numeric_limits<int>::min() << endl;
    cout << " 3 The maximum value for char is " <<
        (int)numeric_limits<char>::max() << endl;
    cout << " 4 The maximum value for int is  " <<
        numeric_limits<int>::max() << endl;
    cout << " 5 The number of bits to represent a char is " <<
        numeric_limits<char>::digits << endl;
    cout << " 6 The number of bits to represent an int is " <<
        numeric_limits<int>::digits << endl;
    cout <<" 7 The number of digits representable in base 10 for float is "
         << numeric_limits<float>::digits10 << endl;
    cout << " 8 Is a char signed?              " <<
        numeric_limits<char>::is_signed << endl;
    cout << " 9 Is an unsigned integer signed? " <<
        numeric_limits<unsigned int>::is_signed << endl;
    cout << "10 Is an integer an integer? " <<
        numeric_limits<int>::is_integer << endl;
    cout << "11 Is a float an integer?   " <<
        numeric_limits<float>::is_integer << endl;
    cout << "12 Is an integer exact? " <<
        numeric_limits<int>::is_exact << endl;
    cout << "13 Is a float exact?  " <<
        numeric_limits<float>::is_exact << endl;
    cout << "14 The radix for float is            "  <<
        numeric_limits<float>::radix << endl;
    cout << "15 The epsilon for float is          " <<
        numeric_limits<float>::epsilon() << endl;
    cout << "16 The round error for float is      " <<
        numeric_limits<float>::round_error() << endl;
    cout << "17 The minimum exponent for float is " <<
        numeric_limits<float>::min_exponent << endl;
    cout << "18 The minimum exponent in base 10   " <<
        numeric_limits<float>::min_exponent10 << endl;
    cout << "19 The maximum exponent is           " <<
        numeric_limits<float>::max_exponent << endl;
    cout << "20 The maximum exponent in base 10   " <<
        numeric_limits<float>::max_exponent10 << endl;
    cout << "21 Can float represent positive infinity?  " <<
        numeric_limits<float>::has_infinity << endl;
    cout << "22 Can double represent positive infinity? " <<
        numeric_limits<double>::has_infinity << endl;
    cout << "23 Can int represent positive infinity? " <<
        numeric_limits<int>::has_infinity << endl;
    cout << "24 Can float represent a NaN?           " <<
        numeric_limits<float>::has_quiet_NaN << endl;
    cout << "25 Can float represent a signaling NaN? " <<
        numeric_limits<float>::has_signaling_NaN << endl;
    cout << "26 Does float allow denormalized values?   " <<
        numeric_limits<float>::has_denorm << endl;
    cout << "27 Does float detect denormalization loss? " <<
        numeric_limits<float>::has_denorm_loss << endl;
    cout << "28 Representation of positive infinity for float " <<
        numeric_limits<float>::infinity() << endl;
    cout << "29 Representation of quiet NaN for float         " <<
        numeric_limits<float>::quiet_NaN() << endl;
    cout << "30 Minimum denormalized number for float         " <<
        numeric_limits<float>::denorm_min() << endl;
    cout << "31 Minimum positive denormalized value for float " <<
        numeric_limits<float>::denorm_min() << endl;
    cout << "32 Does float adhere to IEC 559 standard?  " <<
        numeric_limits<float>::is_iec559 << endl;
    cout << "33 Is float bounded? " <<
        numeric_limits<float>::is_bounded << endl;
    cout << "34 Is float modulo?  " <<
        numeric_limits<float>::is_modulo << endl;
    cout << "35 Is int modulo?    " <<
        numeric_limits<int>::is_modulo << endl;
    cout << "36 Is trapping implemented for float?    " <<
        numeric_limits<float>::traps << endl;
    cout << "37 Is tinyness detected before rounding? " <<
        numeric_limits<float>::tinyness_before << endl;
    cout << "38 What is the rounding style for float? " <<
        (int)numeric_limits<float>::round_style << endl;
    cout << "39 What is the rounding style for int? " <<
        (int)numeric_limits<int>::round_style << endl;
    cout << "40 How does a float represent a signaling NaN? " <<
        numeric_limits<float>::signaling_NaN() << endl;
    cout << "41 Is int specialized? " <<
        numeric_limits<int>::is_specialized << endl;
}

Output

 1 The minimum value for char is -128
 2 The minimum value for int is  -2147483648
 3 The maximum value for char is 127
 4 The maximum value for int is  2147483647
 5 The number of bits to represent a char is 7
 6 The number of bits to represent an int is 31
 7 The number of digits representable in base 10 for float is 6
 8 Is a char signed?              1
 9 Is an unsigned integer signed? 0
10 Is an integer an integer? 1
11 Is a float an integer?   0
12 Is an integer exact? 1
13 Is a float exact?  0
14 The radix for float is            2
15 The epsilon for float is          1.19209e-007
16 The round error for float is      0.5
17 The minimum exponent for float is -125
18 The minimum exponent in base 10   -37
19 The maximum exponent is           128
20 The maximum exponent in base 10   38
21 Can float represent positive infinity?  1
22 Can double represent positive infinity? 1
23 Can int represent positive infinity? 0
24 Can float represent a NaN?           1
25 Can float represent a signaling NaN? 1
26 Does float allow denormalized values?   1
27 Does float detect denormalization loss? 1
28 Representation of positive infinity for float 1.#INF
29 Representation of quiet NaN for float         1.#QNAN
30 Minimum denormalized number for float         1.4013e-045
31 Minimum positive denormalized value for float 1.4013e-045
32 Does float adhere to IEC 559 standard?  1
33 Is float bounded? 1
34 Is float modulo?  0
35 Is int modulo?    1
36 Is trapping implemented for float?    1
37 Is tinyness detected before rounding? 1
38 What is the rounding style for float? 1
39 What is the rounding style for int? 0
40 How does a float represent a signaling NaN? 1.#QNAN
41 Is int specialized? 1

Anforderungen

Header: <limits>

Siehe auch

Konzepte

Standardvorlagenbibliotheks-Beispiele