This templated class provides various information about the built-in types.

Limits for numeric values are defined in the <limits> header. The templated values of numeric_limits provide system-dependent numerical representations of the C++ data types. Use the appropriate function given the data type as the template argument as shown in the table below. Note that numeric_limits can be overloaded for user-defined types as well.

Method or constant	Return	Description
is_specialized	bool
radix	int	base of exponent
digits	int	number of radix digits in mantissa
digits10	int	number of base 10 digits in mantissa
is_signed	bool
is_integer	bool
is_exact	bool
min()	<type>	smallest number that can be respresented (not the most negative)
max()	<type>	largest number
epsilon()	<type>	inherent representation error value, so that 1 + epsilon > 1
round_error()	<type>	maximum rounding adjustment possible
infinity()	<type>
quiet_NaN()	<type>	invalid number that does not signal floating point error
signaling_NaN()	<type>	invalid number that signals floating point error
denorm_min()	<type>
min_exponent	int
min_exponent10	int
max_exponent	int
max_exponent10	int
has_infinity	bool
has_quiet_NaN	bool
has_signaling_NaN	bool
has_denorm	<type>_denorm_style
has_denorm_loss	bool
is_iec559	bool	conforms to IEC-559
is_bounded	bool
is_modulo	bool
traps	bool
tinyness_before	bool
round_style	float_round_style { round_to_nearest, … }

The most common usage is in bounds checking, to determine the minimum and maximum values a data type can hold. The following code prints out the minimum and maximum values for a short on the system it is run.

  #include <limits>
  std::cout << "Maximum short value: " << std::numeric_limits<short>::max() << std::endl;
  std::cout << "Minimum short value: " << std::numeric_limits<short>::min() << std::endl;