This is the first game I ever programmed into a computer. It must have been in the late 70s, and I didn’t write it myself: My father wrote it down for me so I could punch it in. It didn’t run on a real computer, but on his programmable HP calculator, something that hardly anyone had heard of in those days.
The game is “guess a number”: The computer thinks up a random number, the player makes guesses. I learned the concept of binary search fairly easy in life.
I found this when cleaning out an old cupboard at home, together with a bunch of other things that fall safely into the category of “Memorabilia that I cannot possibly throw away. Ever”.