Those companies that judge output by lines of code are asking for this

Good solution! I think you should show the last 3 lines that makes it work tho. FIFY:

private bool IsEven(int number){
    if (number == 1) return false;
    else if (number == 2) return true;
    else if (number == 0) return true;
    else if (number == -1) return false;
    else return !IsEven(abs(number) - 1);
}

Not sure why people still implement this themselves when there are APIs that will do it for you, like https://isevenapi.xyz/

I’ve actually seen this type of code produced by a human-being who was trying to write good code. It was one of the students in my introduction to programming class in university, we had to write a function that squared a number or something, and he had written hundreds of lines of if-statements. Sometimes you just use what you know to complete an assignment I guess 🤷