CODEWITHSUNDEEP
javaloopsfor-loopwhile-loop
Richard
Richard

Reputation: 8935

Java conditional loop

I am trying to loop on an object, until a condition is met.

For example:

Input input = new inputFile(fileName);
input.nextMove();  // returns the next line - EOF returns null

So I want to do something like:

for (int[] move = input.nextMove(); move != null) {
    System.out.println(Arrays.toString(move));
}

I.E. loop until the end of file.

Question

What's the best way to loop over the object?

Upvotes: 2

Views: 101

Answers (2)

Andrew
Andrew

Reputation: 49606

It's a typical Iterator pattern

while(iterator.hasNext()) {
    T element = iterator.next();
}

which, for your case, can be adjusted to

int[] move;
while((move = input.nextMove()) != null) {
    System.out.println(Arrays.toString(move));
}

Upvotes: 4

MC Emperor
MC Emperor

Reputation: 22967

Well, you could do

int[] line;
while ((line = input.nextMove()) != null) { ... }

assuming that nextMove() returns an int[].

This construct assigns the result of nextMove() to line, which is then available in the while body. You see here that such an assignment can be used as value-producing expression, and hence this can be compared. In this case, the loop breaks if line is null.

Upvotes: 0

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