std::rand

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Pseudo-random number generation
Engines and engine adaptors
linear_congruential_engine (C++11)
mersenne_twister_engine (C++11)
subtract_with_carry_engine (C++11)
discard_block_engine (C++11)
independent_bits_engine (C++11)
shuffle_order_engine (C++11)
Generators
random_device (C++11)
Distributions
Uniform distributions
uniform_int_distribution (C++11)
uniform_real_distribution (C++11)
generate_canonical (C++11)
Bernoulli distributions
bernoulli_distribution (C++11)
binomial_distribution (C++11)
negative_binomial_distribution (C++11)
geometric_distribution (C++11)
Poisson distributions
poisson_distribution (C++11)
exponential_distribution (C++11)
gamma_distribution (C++11)
weibull_distribution (C++11)
extreme_value_distribution (C++11)
Normal distributions
normal_distribution (C++11)
lognormal_distribution (C++11)
chi_squared_distribution (C++11)
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.

Contents

[edit] Parameters

(none)

[edit] Return value

Pseudo-random integral value between 0 and RAND_MAX.

[edit] 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

[edit] See also

initializes pseudo-random number generator
(function)