For loop in the form of : "for (A b : c)" in Java

Question

This is the first time that I've seen this kind of syntax :

// class Node
public class Node { 

...
...

}

public class Otherclass { ... }

Otherclass graph = new Otherclass();

// getSuccessors is a method of Otherclass class 

Node currentNode ;

List<Node> successors = graph.getSuccessors(currentNode);

// weird for loop 

for (Node son : successors) { 

// do something 

}

What is that for loop ? some kind of a Matlab syntax ?

Is there any other way to write that for loop ?

Regards

Answer 1

That is a for-each loop (also called an enhanced-for.)

for (type var : arr) { //could be used to iterate over array/Collections class
    body-of-loop
}

The basic for loop was extended in Java 5 to make iteration over arrays and other collections more convenient. This newer for statement is called the enhanced for or for-each

(Documentation)

Answer 2

It's a for each loop. You could also write it like this:

for(int i = 0; i < successors.size(); i++) {
    Node son = successors.get(i);
}

Though the only time I'd personally do that is when the index is needed for doing something other than accessing the element.