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std::srand(3)		       C++ Standard Libary		   std::srand(3)

NAME
     std::srand - std::srand

Synopsis
	Defined in header <cstdlib>
	void srand( unsigned seed );

	Seeds  the  pseudo-random  number generator used by std::rand() with the
     value seed.

	If std::rand() is used before any calls to srand(), std::rand()  behaves
     as if it was
	seeded with srand(1).

	Each  time std::rand() is seeded with the same seed, it must produce the
     same
	sequence of values.

	srand() is not guaranteed to be thread-safe.

Parameters
	seed - the seed value

Return value
	(none)

Notes
	Generally speaking, the pseudo-random number generator	should	only  be
     seeded once,
	before	any  calls to rand(), at the start of the program. It should not
     be repeatedly
	seeded, or reseeded every time you wish  to  generate  a  new  batch  of
     pseudo-random
	numbers.

	Standard  practice is to use the result of a call to std::time(0) as the
     seed.
	However, std::time returns a std::time_t value, and std::time_t  is  not
     guaranteed to
	be an integral type. In practice, though, every major implementation de-
     fines
	std::time_t  to  be  an  integral  type, and this is also what POSIX re-
     quires.

Example
     // Run this code

      #include <cstdlib>
      #include <ctime>
      #include <iostream>

      int main()
      {
	  std::srand(std::time(0)); // use current time as seed for random  gen-
     erator
	  std::cout  <<  "Random  value  on  [0,  "  <<  RAND_MAX  <<  "]:  " <<
     std::rand() << '\n';
      }

Possible output:
      Random value on [0, 2147483647]: 1373858591

See also
	rand	 generates a pseudo-random number
		 (function)
	RAND_MAX maximum possible value generated by std::rand
		 (macro constant)
	reseed	 reseeds the per-thread random engine
		 (function)
	C documentation for
	srand

http://cppreference.com 	   2024.06.10			   std::srand(3)
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