Java Three programs to Iterate a Arraylist

Java Three programs to Iterate a Arraylist . Here are three different ways to iterate through an ArrayList in Java, each with a step-by-step explanation:

Method 1: Using a for-loop 

java
import java.util.ArrayList;

public class ArrayListIterationExample {

    public static void main(String[] args) {
        // Create an ArrayList of Strings
        ArrayList<String> list = new ArrayList<>();
        list.add("MEEERUT");
        list.add("LONDON");
        list.add("USA");

        // Iterate using a for-loop
        System.out.println("Iterating using a for-loop:");
        for (int ivar = 0; ivar  < list.size(); ivar ++) {
            String element = list.get(ivar );
            System.out.println(element);
        }
    }
}

Explanation:
1. ArrayList Creation: We first create an ArrayList named list and add three elements (“Apple”, “Banana”, “Cherry”).
2. For-loop: We use a standard for loop to iterate through the ArrayList.
– list.size() gives the number of elements in the ArrayList.
– list.get(i) retrieves the element at index i.
– System.out.println(element) prints each element.

Method 2: Using an enhanced for-loop (for-each loop) 

java
import java.util.ArrayList;

public class ArrayListIteration_Example {

    public static void main(String[] args) {
        // Create an ArrayList of Strings
        ArrayList<String> list = new ArrayList<>();
        list.add("mahesh");
        list.add("Suresh");
        list.add("Naman");

        // Iterate using an enhanced for-loop
        System.out.println("Iterat using an for-loop:");
        for (String elements : list) {
            System.out.println(elements);
        }
    }
}

Explanation:
1. ArrayList Creation: Same as before, we create an ArrayList named list.
2. Enhanced for-loop: This loop simplifies iteration by directly accessing each element of the ArrayList.
– for (String element : list) iterates through each element in list.
– element represents the current element in each iteration.
– System.out.println(element) prints each element.

Method 3: Using Iterator 

java
import java.util.ArrayList;
import java.util.Iterator;

public class ArrayListIteration_Example {

    public static void main(String[] args) {
        // Create an ArrayList of Strings
        ArrayList<String> list = new ArrayList<>();
        list.add("Ritu");
        list.add("Neha");
        list.add("Jully");

        // Iterate using an Iterator
        System.out.println("Iterating using an Iterator Example Java:");
        Iterator<String> iterator = list.iterator();
        while (iterator.hasNext()) {
            String ele = iterator.next();
            System.out.println(ele);
        }
    }
}

Explanation:
1. ArrayList Creation: Again, we create an ArrayList named list.
2. Iterator: We obtain an iterator using list.iterator().
– iterator.hasNext() checks if there are more elements to iterate over.
– iterator.next() returns the next element in the ArrayList.
– System.out.println(element) prints each element.

Summary of Steps:

– Create ArrayList: Initialize an ArrayList and add elements to it.
– For-loop: Use a standard for loop to iterate over the ArrayList by index.
– Enhanced for-loop: Utilize a simplified for-each loop to iterate directly over elements.
– Iterator: Obtain an iterator and use it to traverse through the ArrayList.

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