Question

Is there an elegant way in java to check if an int is equal to, or 1 larger/smaller than a value.

For example, if I check x to be around 5. I want to return true on 4, 5 and 6, because 4 and 6 are just one away from 5.

Is there a build in function to do this? Or am I better off writing it like this?

int i = 5;
int j = 5;
if(i == j || i == j-1 || i == j+1)
{
    //pass
}
//or
if(i >= j-1 && i <= j+1)
{
    //also works
}

Of course the above code is ugly and hard to read. So is there a better way?

Answer 1

Find the absolute difference between them with Math.abs

private boolean close(int i, int j, int closeness){
    return Math.abs(i-j) <= closeness; 
}

Based on @GregS comment about overflowing if you give Math.abs a difference that will not fit into an integer you will get an overflow value

Math.abs(Integer.MIN_VALUE - Integer.MAX_VALUE) //gives 1

By casting one of the arguments to a long Math.abs will return a long meaning that the difference will be returned correctly

Math.abs((long) Integer.MIN_VALUE - Integer.MAX_VALUE) //gives 4294967295

So with this in mind the method will now look like:

private boolean close(int i, int j, long closeness){
    return Math.abs((long)i-j) <= closeness; 
}