C Programming Tutorial 32 – Modulus Operator

Did you read the last blog on Arithmetic Operators? Are you new here? Start at the beginning, Intro to C!

This video is going to introduce you to a new operator called the modulus operator (%).

In the last video I gave you this example:

I told you that the value of y is going to be 1.  Did you figure out what this operator does? Well it actually takes the remainder.  I’ve always been pretty bad at visualizing a remainder, so I use imagery. Imagine you have a pizza with 5 slices and you want to share the pizza with your pet rat, Pepper Jack.

Well you give a piece to Pepper Jack, a piece to you, a piece to pepper jack, and then another piece to you.  Now, you have one left over:

Now you might suggest just ripping the pizza in half, but you have to realize that piecesOfPizza is an integer.  This means that we cannot split the piece in half.

This brings up the good point that the modulus operator is designed to work with integers.  That’s because if you were using numbers of type double here, you and your pet rat would both get 2.5 pieces of pizza and the remainder would be zero.  The modulus operator would be useless working with floating point numbers.

You can do a lot of cool things with the modulus operator.  One example is figuring out if a number is even or odd. if you divide a number by 2 and the remainder is anything but 0, then you do not have an odd number.

That is all for the modulus operator.  In the next video we are going to learn our first unary operator.

In the next blog we are going to be discussing all Unary Plus and Minus. Check it out!