RAND_MAX

 

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Random number 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)

 

Defined in header <cstdlib>
#define RAND_MAX /*implementation defined*/

Expands to an integer constant expression equal to the maximum value returned by the function std::rand. This value is implementation dependent. It's guaranteed that this value is at least 32767.

Example

Run this code

#include <climits>#include <cstdlib>#include <ctime>#include <iostream>   int main(){// use current time as seed for random generatorstd::srand(std::time(NULL));   std::cout<<"RAND_MAX: "<< RAND_MAX <<'\n'<<"INT_MAX: "<<INT_MAX<<'\n'<<"Random value on [0,1]: "<<static_cast<double>(std::rand())/ RAND_MAX <<'\n';}

Possible output:

RAND_MAX: 2147483647 INT_MAX: 2147483647 Random value on [0,1]: 0.618608

See also

rand	generates a pseudo-random number (function)
srand	seeds pseudo-random number generator (function)
C documentation for RAND_MAX