std::rand

 

C++

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Pseudo-random number generation

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random_device (C++11)

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generate_canonical (C++11)

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bernoulli_distribution (C++11)

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geometric_distribution (C++11)

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poisson_distribution (C++11)

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normal_distribution (C++11)

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cauchy_distribution (C++11)

fisher_f_distribution (C++11)

student_t_distribution (C++11)

Sampling distributions

discrete_distribution (C++11)

piecewise_constant_distribution (C++11)

piecewise_linear_distribution (C++11)

Seed Sequences

seed_seq (C++11)

C library

rand

srand

RAND_MAX

 

Defined in header <cstdlib>
int rand();

Returns a uniformly distributed pseudo-random integral value between ​0​ and RAND_MAX (0 and RAND_MAX included).

srand() should be called before any calls to rand() to initialize the random number generator.

Parameters

(none)

Return value

Pseudo-random integral value between ​0​ and RAND_MAX.

Example

#include <cstdlib>
#include <iostream>
#include <ctime>
 
int main() 
{
    std::srand(time(0)); //use current time as seed for random generator
    int uniform_random_variable = std::rand();
    std::cout << "Uniform random value on [0 " << RAND_MAX << "]: " 
              << uniform_random_variable << '\n';
}

Possible output:

Uniform random value on [0 2147483647]: 1373858591

See also

srand	initializes pseudo-random number generator (function)
C documentation for rand