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numeric_limits::max | ||||
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Defined in header <limits> | ||
static T max()throw(); | (until C++11) | |
staticconstexpr T max()noexcept; | (since C++11) | |
Returns the maximum finite value representable by the numeric typeT. Meaningful for all bounded types.
T | std::numeric_limits<T>::max() |
| /* non-specialized */ | T() |
| bool | true |
| char | CHAR_MAX |
| signedchar | SCHAR_MAX |
| unsignedchar | UCHAR_MAX |
| wchar_t | WCHAR_MAX |
| char8_t(since C++20) | UCHAR_MAX |
| char16_t(since C++11) | UINT_LEAST16_MAX |
| char32_t(since C++11) | UINT_LEAST32_MAX |
| short | SHRT_MAX |
| unsignedshort | USHRT_MAX |
| int | INT_MAX |
| unsignedint | UINT_MAX |
| long | LONG_MAX |
| unsignedlong | ULONG_MAX |
| longlong(since C++11) | LLONG_MAX |
| unsignedlonglong(since C++11) | ULLONG_MAX |
| float | FLT_MAX |
| double | DBL_MAX |
| longdouble | LDBL_MAX |
Demonstrates the use ofmax() with some fundamental types and some standard library typedefs (the output is system-specific):
#include <boost/type_index.hpp>#include <cstddef>#include <iomanip>#include <iostream>#include <limits>#include <type_traits> template<typename T>void print_max_value_of(){constexpr T max{std::numeric_limits<T>::max()}; std::cout<<std::setw(16)<< boost::typeindex::type_id<T>()<<": ";ifconstexpr(std::is_floating_point_v<T>)std::cout<<std::defaultfloat<< max<<" = "<<std::hexfloat<< max<<'\n';else{constexprauto m{static_cast<unsignedlonglong>(max)};std::cout<<std::dec<< m<<" = "<<std::hex<< m<<'\n';}} int main(){std::cout<<std::showbase; print_max_value_of<bool>(); print_max_value_of<short>(); print_max_value_of<int>(); print_max_value_of<std::streamsize>(); print_max_value_of<std::size_t>(); print_max_value_of<char>(); print_max_value_of<char16_t>(); print_max_value_of<wchar_t>(); print_max_value_of<float>(); print_max_value_of<double>(); print_max_value_of<longdouble>();}
Possible output:
bool: 1 = 0x1 short: 32767 = 0x7fff int: 2147483647 = 0x7fffffff long: 9223372036854775807 = 0x7fffffffffffffff unsigned long: 18446744073709551615 = 0xffffffffffffffff char: 127 = 0x7f char16_t: 65535 = 0xffff wchar_t: 2147483647 = 0x7fffffff float: 3.40282e+38 = 0x1.fffffep+127 double: 1.79769e+308 = 0x1.fffffffffffffp+1023 long double: 1.18973e+4932 = 0xf.fffffffffffffffp+16380
[static](C++11) | returns the lowest finite value of the given type, i.e. the most negative value for signed types,0 for unsigned types (public static member function)[edit] |
[static] | returns the smallest finite value of the given non-floating-point type, or the smallest positive normal value of the given floating-point type (public static member function)[edit] |
