# math « Integer « Java Data Type Q&A

### 1. Fastest way to determine if an integer's square root is an integer    stackoverflow.com

I'm looking for the fastest way to determine if a `long` value is a perfect square (i.e. its square root is another integer). I've done it the easy way, by ...

### 2. getting the bottom 16 bits of a Java int as a signed 16-bit value    stackoverflow.com

Hmmm. Consider this program, whose goal is to figure out the best way to get the bottom 16 bits of an integer, as a signed integer.

``````public class SignExtend16 {
public static ...``````

### 3. Pollard rho integer factorization    stackoverflow.com

I am trying to implement Pollard Rho integer factorization in C/C++.Google gives me a Java implementation of the problem here. I don't know Java that well,so what I came up ...

### 4. Java arithmetic int vs. long    stackoverflow.com

I've done some searching on google, but I can't seem to find what I'm looking for. I'm trying to find out some detailed information on the way arithmetic works in Java. ...

### 5. how to get a float from int    stackoverflow.com

i has a int:

``````int f=1234;//or f=23 f=456 ...
``````
i want to get:
``````float result=0.1234; // or 0.23 0.456 ...
``````
dont useing:
``````float result = parseFloat ("0."+f);
``````
what's best way to do? thanks

### 6. float, double and int math in Java    stackoverflow.com

I had some doubts/questions about the math in Java, so I made a small program a screenshot of which you can see in this link:
http://www.imageshuffle.com/view.php?filename=73doublevsfloat.jpg
How are such numbers even ...

### 7. Any trap which we should beware of Integer.MIN_VALUE == -Integer.MIN_VALUE == Math.abs(Integer.MIN_VALUE)    stackoverflow.com

I realize the below code holds true

``````Integer.MIN_VALUE == -Integer.MIN_VALUE == Math.abs(Integer.MIN_VALUE)
``````
This is because when we negate `-2147483648`, it should become `+2147483648`. Since the maximum positive integer can be represented in Java ...

### 8. What happens when you increment an integer beyond its max value?    stackoverflow.com

In Java what happens when you increment an int (or byte/short/long) beyond it's max value ? Does it wrap around to the max negative value ? Does AtomicInteger.getAndIncrement() also behave in the ...

### 9. Are arithmetic operations on double variables with integer values exact?    stackoverflow.com

Let's say I've got two integer values stored in `double` variables, e. g.:

``````double x = 100.0;
double y = 7.0;
``````
May I safely assume that any arithmetic operation on these two double variables ...

### 10. Math.abs returns wrong value for Integer.Min_VALUE    stackoverflow.com

This code:

``````System.out.println(Math.abs(Integer.MIN_VALUE));
``````
Returns `-2147483648` Should it not return the absolute value as `2147483648` ?

### 11. Setting a limit to an int value    stackoverflow.com

I want to set a limit to an `int` value I have in Java. I'm creating a simple health system, and I want my health to stay between 0 and 100. ...

### 12. What is the best way to separate double into two parts "integer & fraction" in java    stackoverflow.com

I have tried to separate 5.6 (for example) by the following method:

``````private static double[] method(double d)
{
int integerPart = 0;
double fractionPart = 0.0;
...``````

### 13. How to set decision variables types like binary, int, double in Apache Commons Math SimplexSolver?    stackoverflow.com

How to set decision variables types like binary, `int`, `double` in Apache Commons Math `SimplexSolver`? The output of the program below is this:

``````332.6666666666667
1.0
8331.666666666668
``````
I want decision variables to be of ...

### 14. Java divison with two integer operands not working?    stackoverflow.com

For some reason my math just returns 0. The value are set, I have checked.

``````int currentSize = 4079;
int totalSize = 500802;

int percentage = ((currentSize/totalSize) * 100);
progdialog.setProgress(percentage);
``````
Percentage always equals percentage. Why?

### 15. How to calculate integer expression in Java    stackoverflow.com

Suppose, I need to calculate `3 * (2 / 3) = 2` but `3 * (2 / 3) = 0` in integer arithmetic. So, it looks like I should use floating-point ...

### 16. x = (int) Math.ceil[ x/2 ] + Math.floor[ x/2 ]    coderanch.com

There isn't a "mathematical" proof because you aren't asking about a mathematical concept, you're asking about how Java implements things. However there's a logical proof which would parallel the mathematical proof of that question. Assuming your "x" is an integer, there are four possibilities: x can be odd or even, and it can be negative or non-negative. Consider each of them ...

### 17. Performing Math on Integer Class    coderanch.com

Does anyone know of an efficient way to perform math on an Integer class or a better way to store an integer value as an object that is mutable? I have a TreeMap that looks like this ... What is the best approach? public TreeMap adjustTreeMap(String key, TreeMap treeMap) { Integer count; if(treeMap.containsKey(key)) { count = treeMap.get(key).intValue(); int i = ...

### 18. simple integer generation using java math classes    forums.oracle.com

I want to generate a integer which should be combination of 2 integer and one int and anytime I call generate it should generate same value for same input and for different combinations it should generate different value. for example I passed to the service two integers 24, 25 and one int 76 assume it generated 242576 I restart jvm to ...