How to print out instance of object that is stored in an array

Question

So I need to print out the different instances of the array. Using the code below. Everything in the array prints out even the portion of the array that is not filled with anything. If i add a break statement in each if statement it only prints the last instance of that array and not everything that that stored.

public static void display(ExampleA[] example)
{ 
    for(int pos = 0; pos < example.length; pos++) 
    {   
        output += "Example number " + (i + 1);
       if(example[pos] instanceof A)
        {
                output += example[pos].toString() + "\n\n";             
        }

        if(example[pos] instanceof B)
        {
            output += example[pos].toString() + "\n\n"; 
        }

    }

What I would like it to do is print out everything in the array grouped together by the instance. and not the whole array that is partially empty.

Answer 1

You can create two output variables, one for the A instances and one for the B instances. Then you can append each instance to its corresponding output variables, and print out the output variables at the end. Here's an example using your code:

public static void display(ExampleA[] example)
{ 
    for(int pos = 0; pos < example.length; pos++) 
    {   
        if(example[pos] instanceof A)
        {
            outputA += "Example number " + (i + 1);
            outputA += example[pos].toString() + "\n\n";             
        }

        if(example[pos] instanceof B)
        {
            outputB += "Example number " + (i + 1);
            outputB += example[pos].toString() + "\n\n"; 
        }

    }

    System.out.println("A:\n" + outputA);
    System.out.println("B:\n" + outputB);
}

You should also look into using StringBuilder to append the Strings, as it's much faster than using +=