Recognizing when to use the modulus operator

Question

I know the modulus (%) operator calculates the remainder of a division. How can I identify a situation where I would need to use the modulus operator?

I know I can u

Answer 1

Modulus is also very useful if for some crazy reason you need to do integer division and get a decimal out, and you can't convert the integer into a number that supports decimal division, or if you need to return a fraction instead of a decimal.

I'll be using % as the modulus operator

For example

2/4 = 0

where doing this

2/4 = 0 and 2 % 4 = 2

So you can be really crazy and let's say that you want to allow the user to input a numerator and a divisor, and then show them the result as a whole number, and then a fractional number.

whole Number = numerator/divisor
fractionNumerator = numerator % divisor
fractionDenominator = divisor

Another case where modulus division is useful is if you are increasing or decreasing a number and you want to contain the number to a certain range of number, but when you get to the top or bottom you don't want to just stop. You want to loop up to the bottom or top of the list respectively.

Imagine a function where you are looping through an array.

Function increase Or Decrease(variable As Integer) As Void
    n = (n + variable) % (listString.maxIndex + 1)  
    Print listString[n]
End Function

The reason that it is n = (n + variable) % (listString.maxIndex + 1) is to allow for the max index to be accounted.

Those are just a few of the things that I have had to use modulus for in my programming of not just desktop applications, but in robotics and simulation environments.