It was my first project in college, In our first year, we learned about binaries, BCDs, etc. I learnt C++(about classes, loops, arrays etc.) and I came up with an idea to create a C++ application which can convert decimal to binary and BCD.   It was easy to come up with an algorithm which converts decimal to binary but the algorithm I created to convert decimal in BCD which didn't work, so I stored the values of each decimal in the switch case. I used ASCII codes in hexadecimal part(the code was a bit inspired by an online tutorial).