Defined in header
void srand( unsigned seed );
Seeds the pseudo-random number generator used by std::rand() with the value
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.
|seed||-||the seed value|
 Return value
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 defines std::time_t to be an integral type, and this is also what POSIX requires.
Random value on [0, 2147483647]: 1373858591
 See also
| generates a pseudo-random number |
| maximum possible value generated by std::rand |
| reseeds the per-thread random engine |
C documentation for srand