How does a random number generator work?

Question

How do random number generator works? (for example in C/C++ Java)

How can I write my own random number generator? (for example in C/C++ Java)

Answer 1

It's also common to seed these types of generators by using something like the fifth decimal of the current clock time which also appears random to us. Add together inputs from a few chaotic systems, e.g. weather data, stock market data, again, using modulus and you have good seed numbers.