How can a computer program randomly pick numbers?

Question

This seems impossible, there has to be a sequence.

Answer 1

It is based on the system clock which is based on the Unix Epoch... and it is an algorithm, so there really is no sequence, but it is not truly random....

Answer 2

Software typically uses pseudo-random number generators. You're right, it's not generally actually random, but rather based off a very convoluted formula that produces results that are random enough for practical purposes. This sequence starts at a "seed" value. Using the same seed value will cause the sequence to repeat with the same values every time. Often, the computer's clock is used as the seed, making it produce different results each time it's used.

More actual randomness is typically needed for cryptographic purposes, since otherwise someone might replicate the conditions that produced your randomness. This can be done by gathering information from your hardware devices, from things that are outside the control of your local computer and its software. This can include asking the user to type something random on the keyboard, the cadence with which they type that text, to the movements of your mouse, the way your computer's clock drifts compared to some other reference clock, the rate and type of network traffic being seen on your network card, and so on.

Answer 3

The algorithms are pseudo-random, they operate based upon complex formulas and can even include semi-random information like how many seconds have passed in the current day, day of the week, number of bytes of free memory at the moment, etc.

Anything which has a sufficiently large number of moving parts so that making a prediction is impossible is for all practical purposes random, regardless of what the underlying systems are.

Answer 4

I did a random stock picker using Excel.

check excel and search for generator, you maybe able to read the formula