Time and Rand Function

[Shashank Gaurav]

Is there exists a datatype "time_t"?If yes how/why do use it?
Why do we pass time(NULL) in srand function to set the seed value?

 //Also what does this code does?
 time_t aTime;
 srand( static_cast<unsigned>(time(&aTime)) );

If possible provide detailed solution.
PS - I am sorry if there are too much questions in one post.

[LB]

http://www.cplusplus.com/reference/ctime/
http://en.cppreference.com/w/cpp/header/ctime

rand and srand are deprecated, it is recommended to use the new random library instead:
http://www.cplusplus.com/reference/random/
http://en.cppreference.com/w/cpp/header/random

See also, the new chrono library:
http://www.cplusplus.com/reference/chrono/
http://en.cppreference.com/w/cpp/header/chrono