# std::uniform_int_distribution

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< cpp‎ | numeric‎ | random

Defined in header `<random>` |  |
template< class IntType = int > class uniform_int_distribution; |  | (since C++11)

Produces random integer values \(\small i\)i, uniformly distributed on the closed interval \(\small[a, b]\)[a, b], that is, distributed according to the discrete probability function

  \({\small P(i|a,b) =}\frac{1}{b - a + 1}\)P(i|a,b) =

  1
  b − a + 1

  .

`std::uniform_int_distribution` satisfies all requirements of RandomNumberDistribution.

### Template parameters

IntType | - | The result type generated by the generator. The effect is undefined if this is not one of short, int, long, long long, unsigned short, unsigned int, unsigned long, or unsigned long long.

### Member types

Member type | Definition
`result_type` (C++11) | IntType
`param_type` (C++11) | the type of the parameter set, see RandomNumberDistribution.

### Member functions

(constructor) (C++11) | constructs new distribution (public member function)
reset (C++11) | resets the internal state of the distribution (public member function)
##### Generation
operator() (C++11) | generates the next random number in the distribution (public member function)
##### Characteristics
a b (C++11) | returns the distribution parameters (public member function)
param (C++11) | gets or sets the distribution parameter object (public member function)
min (C++11) | returns the minimum potentially generated value (public member function)
max (C++11) | returns the maximum potentially generated value (public member function)

### Non-member functions

operator==operator!= (C++11)(C++11)(removed in C++20) | compares two distribution objects (function)
operator<<operator>> (C++11) | performs stream input and output on pseudo-random number distribution (function template)

### Example

This program simulates throwing 6-sided dice.

Run this code

    #include <iostream>
    #include <random>

    int main()
    {
        std::random_device rd;  // a seed source for the random number engine
        std::mt19937 gen(rd()); // mersenne_twister_engine seeded with rd()
        std::uniform_int_distribution<> distrib(1, 6);

        // Use distrib to transform the random unsigned int
        // generated by gen into an int in [1, 6]
        for (int n = 0; n != 10; ++n)
            std::cout << distrib(gen) << ' ';
        std::cout << '\n';
    }

Possible output:

    1 1 6 5 2 2 5 5 6 2

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