将类用于函数而不是使用常规函数是不好的做法吗？

I'm writing a program that calculates the grade needed to score on a final exam to achieve the grade wanted by the user. So Im using a single class for functions that get input and store all the assignment grades, test grades etc and use that information to determine what is needed to be scored on the final to get a desired grade, accounting for different assignment and test weights of course. I'm writing a program that calculates the grade