From cppreference.com
template<classRealType=double>classpiecewise_constant_distribution;(since C++11)std::piecewise_constant_distribution produces random floating-point numbers, which are uniformly distributed within each of the several subintervals [bi, bi+1), each with its own weight wi. The set of interval boundaries and the set of weights are the parameters of this distribution.
The probability density for any bi ≤ x <bi+1 is
wiS (bi+1 - bi)
, where S is the sum of all weights.
std::piecewise_constant_distribution
satisfies all requirements of
.
Template parameters
RealType - The result type generated by the generator. The effect is undefined if this is not one of float, double, or longdouble. Member types
Member type Definition result_type(C++11)RealTypeparam_typethe type of the parameter set, see
. Member functions
constructs new distribution
(public member function)
resets the internal state of the distribution
(public member function)
Generation
generates the next random number in the distribution
(public member function)
Characteristics
returns the distribution parameters
(public member function)
gets or sets the distribution parameter object
(public member function)
returns the minimum potentially generated value
(public member function)
returns the maximum potentially generated value
(public member function)
Non-member functions
Example
Run this code
#include<iostream>#include<map>#include<random>#include<string>intmain(){std::random_devicerd;std::mt19937gen(rd());// 50% of the time, generate a random number between 0 and 1// 50% of the time, generate a random number between 10 and 15std::vector<double>i{0,1,10,15};std::vector<double>w{1,0,1};std::piecewise_constant_distribution<>d(i.begin(),i.end(),w.begin());std::map<int,int>hist;for(intn{};n<1e4;++n)++hist[d(gen)];for(std::cout<<std::hex<<std::uppercase;auto[x,y]:hist)std::cout<<x<<' '<<std::string(y/100,'*')<<'\n';}Possible output:
0 ************************************************** A ********** B ********* C ********* D ********** E ********* References
C++23 standard (ISO/IEC 14882:2024):
28.5.9.6.2 Class template piecewise_constant_distribution [rand.dist.samp.pconst] (p: 1421-1422)
C++20 standard (ISO/IEC 14882:2020):
29.6.9.6.2 Class template piecewise_constant_distribution [rand.dist.samp.pconst] (p: 1207-1208)
C++17 standard (ISO/IEC 14882:2017):
29.6.8.6.2 Class template piecewise_constant_distribution [rand.dist.samp.pconst] (p: 1098-1100)
C++14 standard (ISO/IEC 14882:2014):
26.5.8.6.2 Class template piecewise_constant_distribution [rand.dist.samp.pconst] (p: 962-964)
C++11 standard (ISO/IEC 14882:2011):
26.5.8.6.2 Class template piecewise_constant_distribution [rand.dist.samp.pconst] (p: 955-957)