Greenfoot: Converting a double into an intenger; int cannot be dereferenced

Question

I want to turn any double value into an intenger. I know that the part behind the comma will be lost.

import java.lang.*;

public int doubleToIntenger(double dbl){
    int intenger;
    intenger = intenger.intValue(dbl);
    return intenger;
}

But I'm getting this error as a tooltip in my editor:

int cannot be dereferenced

What do you think `intenger` holds? What would be the value or reference that it is holding currently? what do you think `int intenger;` does? — SMA, Feb 24 '18 at 14:50
Its just a simple declaration. Or did I misunderstand your question? — 1cedsoda, Feb 24 '18 at 14:54
You may not call methods on primitive types. Importing java.lang.* is useless, too. — JB Nizet, Feb 24 '18 at 14:55
Ok, thanks ;D I'm not very experienced in java. I have to find a way to convert an double into an intenger. This was my first idea. — 1cedsoda, Feb 24 '18 at 14:58
Your first idea should be to google for "convert double to integer in Java". Note that it's spelt "integer", not "intenger". Trying random code is not an effective solution. — JB Nizet, Feb 24 '18 at 14:58
One more thing: avoid imports with asterisk - they are a maintenance risk, and there's no need at all to import anything from the `java.lang` package. — Ralf Kleberhoff, Feb 24 '18 at 16:54

score 0 · Accepted Answer · answered Feb 24 '18 at 14:53

0

Just cast double to int, if you only care about before fraction.
But be carefull

double x = 1.999999;
int val = (int)x;// val will be 1

answered Feb 24 '18 at 14:53

miskender

Thanks, this works. I have already tried it with casting, but I got an error. Seems to be something else. – 1cedsoda Feb 24 '18 at 15:04
@phyyyl If the double value comes from a arithmetic operation, you have to think before casting it. Because 1.0 *2 does not have to be resulted as 2.0. It can be 1.99999998. Floating point arithmetic does not produce exact results. – miskender Feb 24 '18 at 15:07
So I should round the value first and than cast it? – 1cedsoda Feb 24 '18 at 15:08
@phyyyl Yes you can do that, but rounding 1,51 will result as 2. You can use epsilon arithmetic if you dont want that behavior. – miskender Feb 24 '18 at 15:11
I would round to the first decimal place after the comma. 1,51 -> 1,5 -> 1 ; 1,999 -> 2,0 -> 2 – 1cedsoda Feb 24 '18 at 15:21

1 Answers1