C++ Library - <limits>

It is a Numeric limits type and it provides information about the properties of arithmetic types (either integral or floating-point) in the specific platform for which the library compiles.
Following is the declaration for std::numeric_limits.
template <class T> numeric_limits; 
template <class T> numeric_limits; 
T − It is a type of class.
In below example for std::numeric_limits.
#include <limits>
#include <iostream>

int main() {
   std::cout << "type\tlowest type\thighest type\n";
   std::cout << "int\t"
      << std::numeric_limits<int>::lowest() << '\t'
      << std::numeric_limits<int>::max() << '\n';
   std::cout << "float\t"
      << std::numeric_limits<float>::lowest() << '\t'
      << std::numeric_limits<float>::max() << '\n';
   std::cout << "double\t"
      << std::numeric_limits<double>::lowest() << '\t'
      << std::numeric_limits<double>::max() << '\n';
}
The sample output should be like this −
type	lowest type	highest type
int	-2147483648	2147483647
float	-3.40282e+38	3.40282e+38
double	-1.79769e+308	1.79769e+308

The fundamental arithmetic types of C++98 should be like this −
The fundamental arithmetic types of C++11 should be like this −
It is a minimum finite value.
For floating types with denormalization (variable number of exponent bits): minimum positive normalized value.
Equivalent to CHAR_MIN, SCHAR_MIN, SHRT_MIN, INT_MIN, LONG_MIN, LLONG_MIN, FLT_MIN, BL_MIN, LDBL_MIN or 0, depending on type.
It is a maximum finite value.
Equivalent to CHAR_MAX, SCHAR_MAX, UCHAR_MAX, SHRT_MAX, USHRT_MAX, INT_MAX, UINT_MAX, LONG_MAX, ULONG_MAX, LLONG_MAX, ULLONG_MAX, UINT_LEAST16_MAX, UINT_LEAST32_MAX, FLT_MAX, DBL_MAX or LDBL_MAX, depending on type.
It is a minimum finite value. (since C++11)
For integral types: the same as min().
For floating-point types: implementation-dependent; generally, the negative of max().
It is for integer types: number of non-sign bits (radix base digits) in the representation.
For floating types: number of digits (in radix base) in the mantissa (equivalent to FLT_MANT_DIG, DBL_MANT_DIG or LDBL_MANT_DIG).
It is a number of digits (in decimal base), that can be represented without change.
Equivalent to FLT_DIG, DBL_DIG or LDBL_DIG for floating types.
It is for integer types: base of the representation.
For floating types: base of the exponent of the representation (equivalent to FLT_RADIX).
It is a machine epsilon (the difference between 1 and the least value greater than 1 that is representable).
Equivalent to FLT_EPSILON, DBL_EPSILON or LDBL_EPSILON for floating types.
It is a minimum negative integer value such that radix raised to (min_exponent-1) generates a normalized floating-point number.
Equivalent to FLT_MIN_EXP, DBL_MIN_EXP or LDBL_MIN_EXP for floating types.
It is a minimum negative integer value such that 10 raised to that power generates a normalized floating-point number.
Equivalent to FLT_MIN_10_EXP, DBL_MIN_10_EXP or LDBL_MIN_10_EXP for floating types.
It is a maximum integer value such that radix raised to (max_exponent-1) generates a representable finite floating-point number.
Equivalent to FLT_MAX_EXP, DBL_MAX_EXP or LDBL_MAX_EXP for floating types.
It is a maximum integer value such that 10 raised to that power generates a normalized finite floating-point number.
Equivalent to FLT_MAX_10_EXP, DBL_MAX_10_EXP or LDBL_MAX_10_EXP for floating types.
It is a denormalized values (representations with a variable number of exponent bits). A type may have any of the following enum values −
denorm_absent, if it does not allow denormalized values.
denorm_present, if it allows denormalized values.
denorm_indeterminate, if indeterminate at compile time.
Minimum positive denormalized value.
It is for types not allowing denormalized values: same as min().
true if the type adheres to IEC-559 / IEEE-754 standard.
An IEC-559 type always has has_infinity, has_quiet_NaN and has_signaling_NaN set to true; And infinity, quiet_NaN and signaling_NaN return some non-zero value.
It is a rounding style. A type may have any of the following enum values −
round_toward_zero, if it rounds toward zero.
round_to_nearest, if it rounds to the nearest representable value.
round_toward_infinity, if it rounds toward infinity.
round_toward_neg_infinity, if it rounds toward negative infinity.
round_indeterminate, if the rounding style is indeterminable at compile time.
For all above types that are not fundamental arithmetic types, the default template definition is used −
template <class T> class numeric_limits {
   public:
      static const bool is_specialized = false;
      static T min() throw();
      static T max() throw();
      static const int digits = 0;
      static const int digits10 = 0;
      static const bool is_signed = false;
      static const bool is_integer = false;
      static const bool is_exact = false;
      static const int radix = 0;
      static T epsilon() throw();
      static T round_error() throw();

      static const int min_exponent = 0;
      static const int min_exponent10 = 0;
      static const int max_exponent = 0;
      static const int max_exponent10 = 0;

      static const bool has_infinity = false;
      static const bool has_quiet_NaN = false;
      static const bool has_signaling_NaN = false;
      static const float_denorm_style has_denorm = denorm_absent;
      static const bool has_denorm_loss = false;
      static T infinity() throw();
      static T quiet_NaN() throw();
      static T signaling_NaN() throw();
      static T denorm_min() throw();

      static const bool is_iec559 = false;
      static const bool is_bounded = false;
      static const bool is_modulo = false;

      static const bool traps = false;
      static const bool tinyness_before = false;
      static const float_round_style round_style = round_toward_zero;
};
template <class T> class numeric_limits {
   public:
      static constexpr bool is_specialized = false;
      static constexpr T min() noexcept { return T(); }
      static constexpr T max() noexcept { return T(); }
      static constexpr T lowest() noexcept { return T(); }
      static constexpr int digits = 0;
      static constexpr int digits10 = 0;
      static constexpr bool is_signed = false;
      static constexpr bool is_integer = false;
      static constexpr bool is_exact = false;
      static constexpr int radix = 0;
      static constexpr T epsilon() noexcept { return T(); }
      static constexpr T round_error() noexcept { return T(); }

      static constexpr int min_exponent = 0;
      static constexpr int min_exponent10 = 0;
      static constexpr int max_exponent = 0;
      static constexpr int max_exponent10 = 0;

      static constexpr bool has_infinity = false;
      static constexpr bool has_quiet_NaN = false;
      static constexpr bool has_signaling_NaN = false;
      static constexpr float_denorm_style has_denorm = denorm_absent;
      static constexpr bool has_denorm_loss = false;
      static constexpr T infinity() noexcept { return T(); }
      static constexpr T quiet_NaN() noexcept { return T(); }
      static constexpr T signaling_NaN() noexcept { return T(); }
      static constexpr T denorm_min() noexcept { return T(); }

      static constexpr bool is_iec559 = false;
      static constexpr bool is_bounded = false;
      static constexpr bool is_modulo = false;

      static constexpr bool traps = false;
      static constexpr bool tinyness_before = false;
};
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