CODEWITHSUNDEEP
javaarraysprintingelement
Fuzail Gilani
Fuzail Gilani

Reputation: 47

How to print elements from an array list

I've looked online for help so far and nothing is working for me. This is what I have right now, can you please tell me what is wrong with it?

import java.util.*;

class employeeProgram{

    public static void main(String[] args){

            for (int count = 0; count < 1; ){

                    Scanner input = new Scanner(System.in);

                    ArrayList<String> employeeNames = new ArrayList<String>();

                    String commnd;

                    print("What would you like to do? (Add, Remove, List, Exit): ");

                    commnd = input.next();

                    if ("Add".equals(commnd)){

                            print("Enter the name of the employee you'd like to add to the list: ");
                            employeeNames.add(input.next());


                    } else if ("Remove".equals(commnd)){

                            print("Enter the name of the employee you'd like to remove from the list: ");

                            employeeNames.remove(input.next());

                    } else if ("List".equals(commnd)){

                            for (int j = 0; j < employeeNames.size(); j++){

                                    println(employeeNames.get(j));
                                    println(j);

                            }


                            //println(employeeNames);

                    } else if ("Exit".equals(commnd)){

                            input.close();
                            break;

                    } else {

                            println("Invalid command.");

                    }
            }
    }
    public static void println(Object x){

            System.out.println(x);

    }
    public static void print(Object x){

            System.out.print(x);

    }

}

The for loop isn't beginning, I know that much because the "println(j)" wasn't working either. When I tried the part that I've commented out, all I got from typing list was "[]" and nothing else. I'm a beginner, and this is my first program using ArrayLists, so thanks in advance to anyone who decides to help me out :)

Upvotes: 0

Views: 16652

Answers (5)

henderso
henderso

Reputation: 1045

I would try something else instead of the for loop:

Although what you have here might technically work, for...loops are for deterministic processes. Here you are using it as an infinite loop that you hope to force break at a later point. This is dangerous and could lead to bugs.

I'd change this:

for (int count = 0; count < 1; ){

to this:

 bool done = false;
 while(!done) {

Then, later, when you want to break out. issue this line:

 done = true;

Upvotes: 0

tom
tom

Reputation: 2712

You are creating a new ArrayList everytime you ask a question. Create it outside of the initial loop.

ArrayList<String> employeeNames = new ArrayList<String>();

Upvotes: 0

Husman
Husman

Reputation: 6909

You need to define your arraylist outsode of your loop, otherwise every iteration creates a new arrayList and the previous changes made to the previous arraylist is garbage collected.

import java.util.*;

class employeeProgram{

    public static void main(String[] args){

            ArrayList<String> employeeNames = new ArrayList<String>();

            for (int count = 0; count < 1; ){

                    Scanner input = new Scanner(System.in);



                    String commnd;

                    print("What would you like to do? (Add, Remove, List, Exit): ");

                    commnd = input.next();

                    if ("Add".equals(commnd)){

                            print("Enter the name of the employee you'd like to add to the list: ");
                            employeeNames.add(input.next());


                    } else if ("Remove".equals(commnd)){

                            print("Enter the name of the employee you'd like to remove from the list: ");

                            employeeNames.remove(input.next());

                    } else if ("List".equals(commnd)){

                            for (int j = 0; j < employeeNames.size(); j++){

                                    println(employeeNames.get(j));
                                    println(j);

                            }


                            //println(employeeNames);

                    } else if ("Exit".equals(commnd)){

                            input.close();
                            break;

                    } else {

                            println("Invalid command.");

                    }
            }
    }
    public static void println(Object x){

            System.out.println(x);

    }
    public static void print(Object x){

            System.out.print(x);

    }

}

Also, there are a few basic changes I would make to this program, first of all - a for loop should be used where you know how many iterations you will do. In your case, a while loop (or better still a do-while loop) is better suited.

Finally creating one liner functions to encapsulate system.out.print and println seem more effort than is necessary.

Upvotes: 0

Hello_Everyone
Hello_Everyone

Reputation: 60

for (int count = 0; count < 1; count++)

Upvotes: 0

Juned Ahsan
Juned Ahsan

Reputation: 68715

Define your employeeNames List outside the first for loop. ArrayList is getting re-intialized with every iteration of the loop.

Upvotes: 2

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