Compress an 'If' Statement

Question

Hoping that this one doesn't cause much trouble in answering, but when writing this out in my Sudoku project, I knew there must be a better way of phrasing this if condition.

Thanks in advance guys.

public static void modVal(int r, int c, int x) {
    if((r>=1 && r<=9) && (c>=1 && c<=9) && (x>=1 && x<=9)) {
        sudoku.set(r,c,x);
    }
}

Answer 1

You could pull out the logic into Boolean values and just test those instead e.g.

boolean validRow = r >= 1 && r <= 9;
boolean validColumn = c >= 1 && c <= 9;
boolean validValue = x >= 1 && x <= 9;
if (validRow && validColumn && validValue) {
    sudoku.set(r, c, x);
}

Or, given that the limits are identical for each (row, column and value all inclusively 1-9), then you could extract that to a method called withinLimits(value) that checks for the value being between 1 and 9.

public boolean withinLimits(int value) {
    return value >= 1 && value <= 9;
}

Then...

if (withinLimits(r) && withinLimits(c) && withinLimits(x)) {
    sudoku.set(r, c, x);
}

Not a great deal better than what you have though, just a little more terse syntactically speaking. And you don't require the additional parentheses either. Just drop them.

Answer 2

java-8

If you're using java 8, there is a way using an IntStream. The advantage is that you could use this with any number of parameters.

public static void modVal(int r,int c,int x){
    if (IntStream.of(r,c,x).allMatch(i -> i>=1 && i<=9)) {
        sudoku.set(r,c,x);
    }
}

---

Explaination

Instream.of(r,c,x) // This will just stream over the data given in parameters.
        .allMatch(Predicate) // This will return true if all the data entered as parameter has been tested within Predicate and returned true.