How to generate “random” but also “unique” numbers?

Question

How are random numbers generated.? How do languages such as java etc generate random numbers, especially how it is done for GUIDs.? i found that algorithms like Pseudorandomnumb

Answer 1

Most random number generators have a way to "randomly" reïnitialize the seed value. (Sometimes called randomize).

If that's not possible, you can also use the system clock to initialize the seed.