std::numeric_limits::max(3)

NAME
std::numeric_limits::max - std::numeric_limits::max

Synopsis
   Defined in header <limits>
   static T max() throw(); (until C++11)
   static constexpr T max() noexcept; (since C++11)
   Returns the maximum finite value representable by the numeric type T. Meaningful for
   all bounded types.

Return value
   T std::numeric_limits<T>::max()
   /* non-specialized */ T()
   bool true
   char CHAR_MAX
   signed char SCHAR_MAX
   unsigned char 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
   unsigned short USHRT_MAX
   int INT_MAX
   unsigned int UINT_MAX
   long LONG_MAX
   unsigned long ULONG_MAX
   long long (since C++11) LLONG_MAX
   unsigned long long (since C++11) ULLONG_MAX
   float FLT_MAX
   double DBL_MAX
   long double LDBL_MAX

Example
   Demonstrates the use of max() with some fundamental types and some standard library
   typedefs (the output is system-specific): // Run this code
 #include <cstddef>
 #include <iostream>
 #include <limits>
 #include <string_view>
 #include <type_traits>
 template<typename T>
 void print_max_twice(std::string_view type)
 {
     constexpr T max_value {std::numeric_limits<T>::max()};
     std::cout << type << ": ";
     if constexpr (std::is_floating_point_v<T>)
         std::cout << std::defaultfloat << max_value << " or "
                   << std::hexfloat << max_value << '\n';
     else
         std::cout << std::dec << static_cast<unsigned long long>(max_value) << " or "
                   << std::hex << static_cast<unsigned long long>(max_value) << '\n';
 }
 int main()
 {
     std::cout << std::showbase;
     print_max_twice<bool>("bool");
     print_max_twice<short>("short");
     print_max_twice<int>("int");
     print_max_twice<std::streamsize>("streamsize");
     print_max_twice<std::size_t>("size_t");
     print_max_twice<char>("char");
     print_max_twice<char16_t>("char16_t");
     print_max_twice<wchar_t>("wchar_t");
     print_max_twice<float>("float");
     print_max_twice<double>("double");
     print_max_twice<long double>("long double");
 }

Possible output:
 bool: 1 or 0x1
 short: 32767 or 0x7fff
 int: 2147483647 or 0x7fffffff
 streamsize: 9223372036854775807 or 0x7fffffffffffffff
 size_t: 18446744073709551615 or 0xffffffffffffffff
 char: 127 or 0x7f
 char16_t: 65535 or 0xffff
 wchar_t: 2147483647 or 0x7fffffff
 float: 3.40282e+38 or 0x1.fffffep+127
 double: 1.79769e+308 or 0x1.fffffffffffffp+1023
 long double: 1.18973e+4932 or 0xf.fffffffffffffffp+16380

See also
   lowest returns the lowest finite value of the given type
   [static] (C++11) (public static member function)
   min returns the smallest finite value of the given type
   [static] (public static member function)