Question

Please explain why the following code snippet fails to compile:

public class ScjpTest{

static void go(int... i){
    System.out.println("In 1");

    for (int x : i){
        System.out.println(x);
    }
}

static void go(int i){
    System.out.println("In 2");

    for (int x : i){
        System.out.println(x);
    }
}

public static void main(String[] args){
    go(1);
    go(1,2);
    go(1,2,3);

}
}

I was testing to see which instance of go() will be called but it is failing with the following error:

ScjpTest.java:16: foreach not applicable to expression type
                  for (int x : i){
                         ^
1 error

I cant for the life of me work out what is wrong with the enhanced for loop.

Thanks

Answer 1

In the first overload, i is an array of integers. That’s how you can iterate over it. In the second overload, it’s just a single integer value. The enhanced for loop only works over Iterable instances and arrays – not single values. You should just write:

System.out.println(i);

as there’s bound to just be one value.