subtract_with_carry::seed
Seeds the engine.
void seed(result_type x0 = 19780503UL);
template<class Gen>
void seed(Gen& gen);
Parameters
Gen
The type of the seed generator.gen
The seed generator.x0
The seed value.
Remarks
Precondition: 0 < x0
The first seed function generates long_lag historical values from the values of type unsigned long returned by successive invocations of gen. Each historical value is gen() % modulus.
The second seed function effectively executes the following code:
linear_congruential<unsigned long, 40014, 0, 2147483563> gen(x0);
seed(gen);
Example
// std_tr1__random__subtract_with_carry_seed.cpp
// compile with: /EHsc
#include <random>
#include <iostream>
typedef std::mt19937 Myeng;
typedef std::subtract_with_carry<unsigned int, 1 << 24,
10, 24> Myceng;
int main()
{
Myeng eng;
Myceng ceng;
Myceng::result_type compval = ceng();
compval = compval; // to quiet "unused" warnings
std::cout << "M == " << Myceng::modulus << std::endl;
std::cout << "S == " << Myceng::short_lag << std::endl;
std::cout << "R == " << Myceng::long_lag << std::endl;
std::cout << "min == " << ceng.min() << std::endl;
std::cout << "max == " << ceng.max() << std::endl;
ceng.seed(); // reseed base engine
std::cout << "a random value == " << ceng() << std::endl;
std::cout << "a random value == " << ceng() << std::endl;
std::cout << "a random value == " << ceng() << std::endl;
Myceng ceng2(eng); // construct with generator
ceng2.seed(eng); // seed with generator
Myceng ceng3(5UL); // construct with unsigned long seed
ceng3.seed(5UL); // seed with unsigned long
return (0);
}
M == 16777216 S == 10 R == 24 min == 0 max == 16777215 a random value == 15039276 a random value == 16323925 a random value == 14283486
Requirements
Header: <random>
Namespace: std