What Did Ada Lovelace's Program Actually Do?

After I had translated Lovelace’s program into C, I was able to run it on my own computer. To my frustration, I kept getting the wrong result. After some debugging, I finally realized that the problem wasn’t the code that I had written. The bug was in the original!

In her “diagram of development,” Lovelace gives the fourth operation as v5 / v4. But the correct ordering here is v4 / v5. This may well have been a typesetting error and not an error in the program that Lovelace devised. All the same, this must be the oldest bug in computing. I marveled that, for ten minutes or so, unknowingly, I had wrestled with this first ever bug.