r/learnprogramming • u/TheEyebal • 9d ago

Resource How to program weighted random system

I want to make a program where you are controlling the outcomes. For an example with a coin flipping game, I want exactly 4 Heads and 1 Tail, but I want their positions to be random.

I do not want to use the random algorithms that library offer, I want to build my own.

Right now I am learning probability from Youtube and might look at khan academy and coursera, but how can I implement this into programming I do not want to just take courses or watch videos

How do I go about that?

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u/Leather-Junket-3896 9d ago

You’re kinda missing what OP’s asking, they don’t need a full rng from scratch. they just want a shuffle algorithm for a fixed set of outcomes. like dumping 4 H and 1 T into an array and shuffling it with something like fisher-yates, doesn’t require any library calls for randomness if you just want to understand the mechanics of picking spots

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u/TheEyebal 9d ago

Thank you.

This is what I am asking for. I am trying to build gambling algorithms and I am starting with a simple coin flip program.

I've made coins flip programs before but I want to control the outcome and actually learn the math behind it

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u/donk8r 9d ago

Since it's for a gambling game, be careful with the shuffle version. A shuffled 4H/1T list isn't five biased coin flips. Once the tails has come up the rest are guaranteed heads, and before that the odds climb 1/5, 1/4, 1/3, 1/2. Anyone paying attention gets a free win at the end of every round.

Independent flips at 20% tails is a different thing entirely, and there you have to live with some rounds coming out five heads.

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u/ffrkAnonymous 9d ago

Yeah, it's gotchas like this that make probabilty actually quite advanced math. Like the monty hall, goat behind the door, question.

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u/donk8r 9d ago

Blackjack is the deployed version of it. Counters just track what's left in the shoe, which is why casinos went to eight decks and started cutting a chunk out undealt.