Question

I have a function that should work on int[] and on String[] now i have made the same function with a int parameter and an String parameter however if it has to go this way its a bit copy paste work and doesn’t look very organized is there a way to solve this and put these 4 functions in 2?

    static public void print(String s)
    {
        System.out.println(s);
    }

    static public void print(int s)
    {
        System.out.println(s);
    }

    static public void printArray(String[] s)
    {
        for (int i=0; i<s.length; i++)
            print(s[i]);
    }

    static public void printArray(int[] s)
    {
        for (int i=0; i<s.length; i++)
            print(s[i]);
    }

Thanks
Matthy

Answer 1

With autoboxing / autounboxing, you can do this:

public static void print(Object s) {
  System.out.println(s.toString());
}

public static <T> void printArray(T[] arr) {
  for (T t : arr) {
    print(t);
  }
}

The one drawback is that the argument to printArray must be an array of a reference type, but unlike the varargs solution this will work for any reference type.

Edit: regarding the varargs solution and @matthy’s question about combining the two methods into one (ie generifying it), you could also do something like this:

static public <T> void print(T... ts) {
    for (T t : ts) {
      System.out.print(t + " ");
    }
    System.out.println("");
}

However, you still cannot call it on an array of primitives:

int[] x = { 1, 2 };
print(x);

Because Java takes T to be int[] and will execute the toString method of the array rather than iterate through the contents. If you call it on an array of Integer or other reference type then it will work also.