public member function
<random>
| (1) | explicit normal_distribution ( result_type mean = 0.0, result_type stddev = 1.0 ); |
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| (2) | explicit normal_distribution ( const param_type& parm ); |
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Construct normal distribution
Constructs a normal_distribution object, adopting the distribution parameters specified either by mean and stddev or by object parm.
Parameters
- mean
- Mean of the distribution (its expected value, μ). Which coincides with the location of its peak.
result_type is a member type that represents the type of the random numbers generated on each call to operator(). It is defined as an alias of the first class template parameter (RealType). - stddev
- Standard deviation (σ): The square root of variance, representing the dispersion of values from the distribution mean.
This shall be a positive value (σ>0).
result_type is a member type that represents the type of the random numbers generated on each call to operator(). It is defined as an alias of the first class template parameter (RealType). - parm
- An object representing the distribution's parameters, obtained by a call to member function param.
param_type is a member type.
Example
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| // normal_distribution example #include <iostream> #include <chrono> #include <random> int main() { // construct a trivial random generator engine from a time-based seed: unsigned seed = std::chrono::system_clock::now().time_since_epoch().count(); std::default_random_engine generator (seed); std::normal_distribution<double> distribution (0.0,1.0); std::cout << "some Normal-distributed(0.0,1.0) results:" << std::endl; for (int i=0; i<10; ++i) std::cout << distribution(generator) << std::endl; return 0; }
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Possible output:
some Normal-distributed(0.0,1.0) results: -0.246719 0.189872 -1.53603 -1.58534 0.0569692 2.22 1.34839 -0.512007 0.450768 -0.0999992 |