I like to think I'm decent with C, and I thought I would be able to make my own solitaire, but just trying to wrap my head around how in the world I was supposed to lay out all the cards in memory and keep track of all the different states had me giving up pretty quickly.

Probably depends on the kind of solitaire IMO.

I feel like Klondike, -should- be simple enough with a set of vectors/arrays/lists, the biggest thing is making sure you have the traversal logic right. [0]

[0] - I mean, here's an example in VB.NET, where a lot of the game logic is FBOW integrated into the form logic, but hey it apparently is NET8! https://github.com/DualBrain/Solitaire/blob/master/Solitaire...

I'd start by identifying all the known boundaries:

52 cards, so each card can be represented by a byte.

Cards are arranged into 4 stacks of up to 13 cards each, 7 columns of up to 13 cards each, and a pile of up to 24 remaining cards. (You don't need two piles of remaining cards.)

That's 167 (4 * 13 + 7 * 13 + 24) bytes for the cards, 12 bytes to store lengths, and 1 byte to store the current index in the pile of remaining cards. It's a fixed number of fixed-length byte arrays and a fixed number of bytes to track lengths and one index.