evaluating variable int/string

Question

 int x = 20;


 double d = 3.1416;


 String s ="H";

those are my variables and I have to give the type the next lines evaluate to.

d/x + ""; 

is evaluating to double variable type (0.15708), is that correct?

Answer 1

You'd be right if we didn't have that pesky "" at the end!

Add "" to the end of something like this makes it into a String . It can actually be a handy shortcut - instead of having to use something like String.valueOf() , you could just do 4/2 + "" , which makes it into a string.

To reiterate,

d/x would be a double , since you are adding a floating point.

But a double + "" = String .

I hope that helps. Good luck :)

Answer 2

You are wrong. d/x + ""; is a String .

This happens because when you are using the + operator, if any of the 2 sides is a String , then string concatenation happens and of course the result is a String .

By the way you can check that indeed it is a String by using the getClass() method. Note that if you remove the "" and use the getClass() you will get an error. This happens because d/x is a double , ie a primitive type, so it can't use the method getClass() .

In your example:

System.out.println((d/x + "").getClass()); will return java.lang.String