How to display the content of Java ArrayList?

Question

This is my Data class:

public class Data {
    private String name;
    private int age;
    Data(String n,int a){
        name = n;
        age = a;
    }

    public String getName(){
        return(name);
    }

    public void setName(String n){
        name = n;
    }

    public int getAge(){
        return(age);
    }

    public void setAge(int a){
        age = a;
    }

    public void Print(){
        System.out.print(("("+GetName()));
        System.out.print(",");
        System.out.print(GetAge());
        System.out.print(") ");
    }
}

This is my CS1702_Lab5 class that uses ArrayList and that is supposed to print the content of ArrayList:

import java.util.ArrayList;

public class CS1702_Lab5 {

    public static void main(String args[]){
        ArrayList<Data> data = new ArrayList<Data>();
        data.add(new Data("Fred", 21));
    }

    private static void PrintDataArray(ArrayList<Data> data) {
        for(int i=0;i<data.size();++i){
            data.get(i).Print();
        }
    }
}

I am trying to add new Data which is a StringName and IntAge and then display it but it doesn't seem to work. The console is empty nothing is printed.

Thank you in advance!

If you want to call the print method, you have to add it to your main, it won't automagically know what you meant it to do. Computers are extremely pedantic. — Peter Lawrey
– Peter Lawrey, Commented Feb 25, 2014 at 12:59

Taryn · Accepted Answer · 2014-02-26 14:49:02Z

3

You never called your print method from main().

edited Feb 26, 2014 at 14:49

Taryn

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answered Feb 25, 2014 at 12:54

Thom

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Comments

score 1 · Accepted Answer · 2014-02-25 13:26:41Z

1

You have to call PrintDataArray() method from main():

import java.util.ArrayList;

public class CS1702_Lab5 {
    public static void main(String args[]) {
        ArrayList<Data> data = new ArrayList<Data>();
        data.add(new Data("Fred", 21));
        PrintDataArray(data);  // YOU NEED TO ADD THIS LINE.
    }

    private static void PrintDataArray(ArrayList<Data> data) {
        for (int i = 0; i < data.size(); ++i) {
            data.get(i).Print();
        }
    }


}

edited Feb 25, 2014 at 13:26

answered Feb 25, 2014 at 12:57

user508434

Comments

Philipp Sander · Accepted Answer · 2014-02-25 12:57:27Z

1

public static void main(String args[])
{
    ArrayList<Data> data = new ArrayList<Data>();
    data.add(new Data("Fred", 21));
    PrintDataArray(data);
}

you never called PrintDataArray

answered Feb 25, 2014 at 12:57

Philipp Sander

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Comments

Nambi · Accepted Answer · 2014-02-25 12:57:13Z

0

Call the Print PrintDataArray method in the main method

public static void main(String args[]) {
{
ArrayList<Data> data = new ArrayList<Data>();
data.add(new Data("Fred", 21));
here>PrintDataArray(data);
}
}

answered Feb 25, 2014 at 12:57

Nambi

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Comments

earthmover · Accepted Answer · 2014-02-25 12:57:16Z

0

You haven't call the method PrintDataArray(data) in your main method...

public static void main(String args[])
{
    ArrayList<Data> data = new ArrayList<Data>();
    data.add(new Data("Fred", 21));
    CS1702_Lab5.PrintDataArray(data);
}

Note: please read naming conventions in Java and try to use them.

answered Feb 25, 2014 at 12:57

earthmover

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Comments

ItachiUchiha · Accepted Answer · 2014-02-25 12:57:37Z

0

Add PrintDataArray() inside your main method

public static void main(String args[])
{
    {
    ArrayList<Data> data = new ArrayList<Data>();
    data.add(new Data("Fred", 21));
    PrintDataArray(data);
    }
    }

    private static void PrintDataArray(ArrayList<Data> data) 
    {
        for(int i=0;i<data.size();++i)

        {
            data.get(i).Print();
        }
    }
}

answered Feb 25, 2014 at 12:57

ItachiUchiha

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