Made even_or_odd.c more concise

[rocketry1969]

I rewrote the even or odd file replacing the if/else statement with a ternary operator and using the bitwise and operator over the more conventional and conditional operator. By doing this you not only make the code more concise, but using bit operators are faster than other operators. Especially if this repo is for educational purposes it is a neat tool to be introduced to as a beginner.