RAND_MAX
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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.
[edit] Example
Run this code
#include <climits> #include <cstdlib> #include <ctime> #include <iostream> int main() { // use current time as seed for random generator std::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
[edit] See also
C documentation for RAND_MAX