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C# C# Basics (Retired) Perform Math

Posted by Lee Puckett
Lee Puckett
12,539 Points

I don't get how modulus works. In the example he says the modulus is one, but I don't see how he got that.

That's all

3 Answers

Andrew Trachtman
Andrew Trachtman
3,680 Points
Andrew Trachtman
Andrew Trachtman
3,680 Points

This confused me as well. The trick here is that everything is performed from left to right (It threw me off seeing 21%3 not return 0, but then I realized I was getting ahead of myself).

Let me break it down for you.

5 + 2 - ( (3*7) / 3 ) % 3

So we get that 3*7 = 21
5 + 2 - ( 21 / 3 ) % 3

21/3 = 7
5 + 2 - (7) % 3

7/3 = 2 with a remainder of 1. So 7%3 = 1

5 + 2 - 1

Final result:
7 - 1 = 6

I hope this helps clarify things.

Lee Puckett
Lee Puckett
12,539 Points

Thank you very much! I think he just left out some steps in instruction and that confused me.

Ramses Martinez
Ramses Martinez
2,011 Points
Ramses Martinez
Ramses Martinez
2,011 Points

You can also see the model this way...

5 % 3

How many times does the 3 fit the 5?... 1, So 

3 x 1 = 3

Now we search the difference (Residue)

5 - 3 = 2

therefore 

5 % 3 = 2
Lee Puckett
Lee Puckett
12,539 Points

Thanks! He didn't really explain it and since I had never done that operation before, I wasn't sure what I was suppose to be looking for.

Nicholas Rossi
Nicholas Rossi
5,066 Points

I was also very confused by the % operator, as I've never used it before. I would recommend TreeHouse might want to explain this operator a little more clearly. Ramses, your "How many times does x fit into y...?" really helped me out.

Jon Wood
Jon Wood
9,884 Points
Jon Wood
Jon Wood
9,884 Points

Modulus is doing a division on the two numbers and it returns the remainder.