How do I calculate a user's grade in percentage?

Question

I'm trying to make my game give the percentage(%) of a user's grade but I keep getting 0%.

Here's my code :

int win = 2
int Percentage = win/5;
System.out.println();
System.out.println("Your score is : " + win + "/" + "5" + "(" + Percentage *100 + "%" + ")");

Console : Your score is : 2/5(0%)

Possible duplicate of [Why is the result of 1/3 == 0?](http://stackoverflow.com/questions/4685450/why-is-the-result-of-1-3-0) — Andrew Li, May 21 '17 at 05:03

score 6 · Accepted Answer · answered May 21 '17 at 04:47

6

You need to use double (floating point) arithmetic for this. FYI / 5.0 converts the int into a double

double Pct = win / 5.0;

answered May 21 '17 at 04:47

ControlAltDel

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Thank you very much, it worked! Could you explain why using int doesn't work? – Crypto May 21 '17 at 04:51
You could actually make int work (albeit to only two digit accuracy) by multiplying by 100 first. But otherwise integers are only (positive & negative) whole numbers and zero – ControlAltDel May 21 '17 at 04:57
can't I change let's change 20.0% into 20% instead? – Crypto May 21 '17 at 05:01
There are multiple ways to do this. One is DecimalFormat. Another is printf – ControlAltDel May 21 '17 at 05:03

score 1 · Answer 2 · edited May 21 '17 at 06:15

1

The Integer type can only be whole numbers. If you want to create a percentage, you need to use the Double type. You can also use \n to create a new return line in your printout.

double win = 2.0;
double percentage = (win/5) * 100;
System.out.println("\n\n Your score is: " + win + "/5 (" + percentage + "%)");

edited May 21 '17 at 06:15

iamwhoiam

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answered May 21 '17 at 04:52

JTMKoenig

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Double is not a type- it is a class. And double(the primitive) here is more appropriate than Double – ControlAltDel May 21 '17 at 04:59
I always forget to add \n to make newlines. Thanks! :) – Crypto May 21 '17 at 04:59
@ControlAltDel you are right. My mistake. I made edits to use the double primitive. – JTMKoenig May 21 '17 at 05:10

How do I calculate a user's grade in percentage?

2 Answers2