Question

I am trying to check whether one value equals + or – 2 the other value.

This is what i have come across.

    for (int lineNumber : errorLineList) {
        if (lineNumber == startLineNumber
                || lineNumber == (startLineNumber + 1)
                || lineNumber == (startLineNumber + 2)
                || lineNumber == (startLineNumber - 1)
                || lineNumber == (startLineNumber - 2)) {
            lineFound = true;
            break;
        }
    }

But here if i want the tolerance to be 5, then i have to add 10 checks.

Is there any other elegant way to do this in java.

Answer 1

This is often need when using doubles as you can get small rounding errors.

if(Math.abs(lineNumber - startLineNumber) <= 2)

You can change 2 to 5. This is says; if the difference between two values is less than 2. i.e it could be -2, -1, 0, 1 or 2.

For double a similar solution is to test “equality” using

if(Math.abs(a - b) < ERR) // where ERR is 1e-4 or 1e-9

What is a good value of ERR to use depends on the situation.