std::uniform_int_distribution

template <class IntType = int> class uniform_int_distribution;

Uniform discrete distribution

Random number distribution that produces integer values according to a uniform discrete distribution, which is described by the following probability mass function:

This distribution produces random integers in a range [a,b] where each possible value has an equal likelihood of being produced. This is the distribution function that appears on many trivial random processes (like the result of rolling a die).

The distribution parameters, a and b, are set on construction.

To produce a random value following this distribution, call its member function operator().

For a discrete distribution that can have different probabilities for each possible value, see discrete_distribution.

Template parameters

IntType: An integer type. Aliased as member type result_type.
By default, this is int.

Member types

The following aliases are member types of uniform_int_distribution:

member type	definition	notes
`result_type`	The first template parameter (`IntType`)	The type of the numbers generated (defaults to `int`)
`param_type`	not specified	The type returned by member param.

Member functions

(constructor): Construct uniform discrete distribution (public member function)

operator(): Generate random number (public member function)

reset: Reset distribution (public member function)

param: Distribution parameters (public member function)

min: Minimum value (public member function)

max: Maximum value (public member function)

Distribution parameters:

a: Lower bound of range (public member function)

b: Upper bound of range (public member function)

Non-member functions

operator<<: Insert into output stream (function template)

operator>>: Extract from input stream (function template)

relational operators: Relational operators (function template)

Example

// uniform_int_distribution #include <iostream> #include <random> int main() { const int nrolls = 10000; // number of experiments const int nstars = 95; // maximum number of stars to distribute std::default_random_engine generator; std::uniform_int_distribution<int> distribution(0,9); int p[10]={}; for (int i=0; i<nrolls; ++i) { int number = distribution(generator); ++p[number]; } std::cout << "uniform_int_distribution (0,9):" << std::endl; for (int i=0; i<10; ++i) std::cout << i << ": " << std::string(p[i]*nstars/nrolls,'*') << std::endl; return 0; }

Possible output:

uniform_int_distribution (0,9): 0: ********* 1: ********* 2: ********* 3: ********* 4: ********* 5: ********* 6: ********* 7: ********* 8: ********* 9: *********

distributions

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member functions

non-member functions