头文件使用示例

////////////////////////////////////////////////////////////////////// // // Compile options needed: /GX // // <filename> : 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 <iostream> #include <limits> #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<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 a 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 a 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<float>::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<float>::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