limits 头文件使用示例

 

// 
// 
// Compile options needed: /GX
// 
//  :  Numeric.cpp
// 
// 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()
// 
// Written by Linda Koontz
// of Microsoft Product Support Services,
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
// 

/* Compile options needed: /GX
*/ 

#include 
#include 

#if _MSC_VER > 1020   // if VC++ version is > 4.2
   using namespace std;  // std c++ libs implemented in std
   #endif

void main() {
    cout << " 1 The minimum value for char is " <<
        (int)numeric_limits::min() << endl;
    cout << " 2 The minimum value for int is " <<
         numeric_limits::min() << endl;
    cout << " 3 The maximum value for char is " <<
        (int)numeric_limits::max() << endl;
    cout << " 4 The maximum value for int is " <<
        numeric_limits::max() << endl;
    cout << " 5 The number of bits to represent a char is " <<
        numeric_limits::digits << endl;
    cout << " 6 The number of bits to represent an int is " <<
        numeric_limits::digits << endl;
    cout <<" 7 The number of digits representable in base 10 for float is"
         << numeric_limits::digits10 << endl;
    cout << " 8 Is a char signed?              " <<
        numeric_limits::is_signed << endl;
    cout << " 9 Is an unsigned integer signed? " <<
        numeric_limits::is_signed << endl;
    cout << "10 Is a integer an integer? " <<
        numeric_limits::is_integer << endl;
    cout << "11 Is a float an integer?   " <<
        numeric_limits::is_integer << endl;
    cout << "12 Is a integer exact? " <<
        numeric_limits::is_exact << endl;
    cout << "13 Is a float  exact?  " <<
        numeric_limits::is_exact << endl;
    cout << "14 The radix for float is            "  <<
        numeric_limits::radix << endl;
    cout << "15 The epsilon for float is          " <<
        numeric_limits::epsilon() << endl;
    cout << "16 The round error for float is      " <<
        numeric_limits::round_error() << endl;
    cout << "17 The minimum exponent for float is " <<
        numeric_limits::min_exponent << endl;
    cout << "18 The minimum exponent in base 10   " <<
        numeric_limits::min_exponent10 << endl;
    cout << "19 The maximum exponent is           " <<
        numeric_limits::max_exponent << endl;
    cout << "20 The maximum exponent in base 10   " <<
        numeric_limits::max_exponent10 << endl;
    cout << "21 Can float represent positive infinity?  " <<
        numeric_limits::has_infinity << endl;
    cout << "22 Can double represent positive infinity? " <<
        numeric_limits::has_infinity << endl;
    cout << "23 Can int represent positive infinity? " <<
        numeric_limits::has_infinity << endl;
    cout << "24 Can float represent a NaN?           " <<
        numeric_limits::has_quiet_NaN << endl;
    cout << "25 Can float represent a signaling NaN? " <<
        numeric_limits::has_signaling_NaN << endl;
    cout << "26 Does float allow denormalized values?   " <<
        numeric_limits::has_denorm << endl;
    cout << "27 Does float detect denormalization loss? " <<
        numeric_limits::has_denorm_loss << endl;
    cout << "28 Representation of positive infinity for float " <<
        numeric_limits::infinity() << endl;
    cout << "29 Representation of quiet NaN for float         " <<
        numeric_limits::quiet_NaN() << endl;
    cout << "30 Minimum denormalized number for float         " <<
        numeric_limits::denorm_min() << endl;
    cout << "31 Minimum positive denormalized value for float " <<
        numeric_limits::denorm_min() << endl;
    cout << "32 Does float adhere to IEC 559 standard?  " <<
        numeric_limits::is_iec559 << endl;
    cout << "33 Is float bounded? " <<
        numeric_limits::is_bounded << endl;
    cout << "34 Is float modulo?  " <<
        numeric_limits::is_modulo << endl;
    cout << "35 Is int modulo?    " <<
        numeric_limits::is_modulo << endl;
    cout << "36 Is trapping implemented for float?    " <<
        numeric_limits::traps << endl;
    cout << "37 Is tinyness detected before rounding? " <<
        numeric_limits::tinyness_before << endl;
    cout << "38 What is the rounding style for float? " <<
        (int)numeric_limits::round_style << endl;
    cout << "39 What is the rounding style for int? " <<
        (int)numeric_limits::round_style << endl;
    cout << "40 How does a float represent a signaling NaN? " <<
        numeric_limits::signaling_NaN() << endl;
    cout << "41 Is int specialized? " <<
        numeric_limits::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.#IND
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?    0
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.#INF
41 Is int specialized? 1