Looking for "Hard examples" using only if-else-statement

this is more a personal question, so I've been working with c++ about 3 months ago, doing some examples about if-else statement, surfing on the internet I found some great exercises to practice with, the problem is they are "Too basic", I want a challenge to this topic to dominate it... resuming at all, have you guys got some any great if-else exercises to practice with?, if you have it, could you bring them at this post?, thank you.

I have already tried to: -Making Bills -Simulating an ATM -Calculators, etc.

I expect to bring some ideas or examples.