I was studying with Lee OO and OO Gong books, but I couldn't understand anything, so I purchased Jumal Coding's lectures. *I had watched them a few times on YouTube before. After watching the lectures, I wonder why I didn't buy them sooner. The lectures separately cover C language pointers and structure problems, as well as Java constructor problems—which many students find confusing—and it's been a huge help in my understanding. If you are hesitating to buy, go ahead and purchase them right away.