| Common mathematical functions | |||||||||||||||||||||||||||||||
| Mathematical special functions(C++17) | |||||||||||||||||||||||||||||||
| Mathematical constants(C++20) | |||||||||||||||||||||||||||||||
| Basic linear algebra algorithms(C++26) | |||||||||||||||||||||||||||||||
| Data-parallel types (SIMD)(C++26) | |||||||||||||||||||||||||||||||
| Floating-point environment(C++11) | |||||||||||||||||||||||||||||||
| Complex numbers | |||||||||||||||||||||||||||||||
Numeric array (valarray) | |||||||||||||||||||||||||||||||
| Pseudo-random number generation | |||||||||||||||||||||||||||||||
| Bit manipulation(C++20) | |||||||||||||||||||||||||||||||
| Saturation arithmetic(C++26) | |||||||||||||||||||||||||||||||
| Factor operations | |||||||||||||||||||||||||||||||
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| Interpolations | |||||||||||||||||||||||||||||||
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| Generic numeric operations | |||||||||||||||||||||||||||||||
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| C-style checked integer arithmetic | |||||||||||||||||||||||||||||||
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| Member functions | ||||
| Generation | ||||
| Characteristics | ||||
| Non-member functions | ||||
(C++11)(C++11)(until C++20) | ||||
(C++11)(C++11) |
Defined in header <random> | ||
template<class IntType=int> class discrete_distribution; | (since C++11) | |
std::discrete_distribution produces random integers on the interval[0, n), where the probability of each individual integeri is defined aswi/S, that is theweight of theith integer divided by the sum of alln weights.
std::discrete_distribution satisfies all requirements ofRandomNumberDistribution.
Contents |
| IntType | - | The result type generated by the generator. The effect is undefined if this is not one ofshort,int,long,longlong,unsignedshort,unsignedint,unsignedlong, orunsignedlonglong. |
| Member type | Definition |
result_type(C++11) | IntType |
param_type(C++11) | the type of the parameter set, seeRandomNumberDistribution. |
(C++11) | constructs new distribution (public member function)[edit] |
(C++11) | resets the internal state of the distribution (public member function)[edit] |
Generation | |
(C++11) | generates the next random number in the distribution (public member function)[edit] |
Characteristics | |
| obtains the list of probabilities (public member function)[edit] | |
(C++11) | gets or sets the distribution parameter object (public member function)[edit] |
(C++11) | returns the minimum potentially generated value (public member function)[edit] |
(C++11) | returns the maximum potentially generated value (public member function)[edit] |
(C++11)(C++11)(removed in C++20) | compares two distribution objects (function)[edit] |
(C++11) | performs stream input and output on pseudo-random number distribution (function template)[edit] |
#include <iomanip>#include <iostream>#include <map>#include <random> int main(){std::random_device rd;std::mt19937 gen(rd()); std::discrete_distribution<> d({40,10,10,40});std::map<int,int> map; for(int n=0; n<1e4;++n)++map[d(gen)]; for(constauto&[num, count]: map)std::cout<< num<<" generated "<<std::setw(4)<< count<<" times\n";}
Possible output:
0 generated 4037 times1 generated 962 times2 generated 1030 times3 generated 3971 times
