Standard math functions.
Seed the pseudo-random number generator.
When your app starts, the pseudo-random number generator is automatically seeded with a random number that is generated by a high-entropy hardware random number generator.
This function affects subsequent calls to rand() to produce a sequence of numbers for a given seed value. You can use this to either create a different sequence of numbers by always using a different seed or to obtain the same sequence of numbers by reusing the same seed.
The source number used to generate a sequence of pseudo-random numbers
The maximum integer value rand() may return.