# std::negative_binomial_distribution<IntType>::negative_binomial_distribution

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< cpp‎ | numeric‎ | random‎ | negative binomial distribution

negative_binomial_distribution() : negative_binomial_distribution(1) {} | (1) | (since C++11)
explicit negative_binomial_distribution( IntType k, double p = 0.5 ); | (2) | (since C++11)
explicit negative_binomial_distribution( const param_type& params ); | (3) | (since C++11)

Constructs a new distribution object. (2) uses `k` and `p` as the distribution parameters. (3) uses `params` as the distribution parameters.

### Parameters

k | - | the k distribution parameter (number of trial successes)
p | - | the p distribution parameter (probability of a trial generating true)
params | - | the distribution parameter set

### Notes

Requires that 0 < p ≤ 1 and 0 < k.

If `p == 1`, subsequent calls to the `operator()` overload that does not accept a `param_type` object will cause undefined behavior.

The default-constructed `std::negative_binomial_distribution` is equivalent to the default-constructed std::geometric_distribution.

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
P0935R0 | C++11 | default constructor was explicit | made implicit

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