Someone asked in September or October about C programming. I just came across this coupon to enjoy a solid, normally paid, online course: C Programming Masterclass: Build Your Programming Foundation udemy.com/course/c-programming-masterclass-build-your-programming-foundation/?couponCode=A92A65F904B1200AA049
I am not affiliated with them, and I hope that it is appropriate to share such. All the best, Todd
