Java – For Each Loop – Ameerpet Technologies

For-each loop:

It is also called enhanced for loop.
It is since JDK5
For-each loop provides easy syntax to process elements of Array or Collection.

Limitations:

For-each loop can process elements only in forward direction.
For-each loop can process elements one by one only.

Syntax:

for (datatype var : Array/Collection )
{
statements ;
}

Program to display ArrayList using for-each loop:

import java.util.*;
class Code
{
            public static void main(String[] args) {
                        List<Integer> list = new ArrayList<Integer>();
                        for(int i=1 ; i<=5 ; i++)
                                    list.add(i*5);

                        System.out.println(“List is : “);
                        for(Integer x : list)
                                    System.out.println(x);
            }
}

Display ArrayList element by element using for-loop: get(int index) method is used to retrieve each element using its index.

import java.util.*;
class Code
{
            public static void main(String[] args) {
                        List<Integer> list = new ArrayList<Integer>();
                        for(int i=1 ; i<=5 ; i++)
                                    list.add(i*5);

                        System.out.println(“List is : “);
                        for(int i=0 ; i<=list.size()-1 ; i++)
                                    System.out.println(list.get(i));
            }
}

Program to display ArrayList in Reverse Order:

import java.util.*;
class Code
{
            public static void main(String[] args) {
                        List<Integer> list = new ArrayList<Integer>();
                        for(int i=1 ; i<=5 ; i++)
                                    list.add(i*5);

                        System.out.println(“List is : “);
                        for(int i=list.size()-1 ; i>=0 ; i–)
                                    System.out.println(list.get(i));
            }
}

Program to Merge 2 ArrayLists: addAll(Collection c) method is used to merge 2 lists.

import java.util.*;
class Code
{
            public static void main(String[] args)
            {
                        List<Integer> a1 = new ArrayList<Integer>();
                        for(int i=1 ; i<=5 ; i++)
                        {
                                    a1.add(i*5);
                        }
                        System.out.println(“a1 list is : ” + a1);

                        List<Integer> a2 = new ArrayList<Integer>();
                        for(int i=5 ; i>=1 ; i–)
                        {
                                    a2.add(i*5);
                        }
                        System.out.println(“a1 list is : ” + a1);

                        a1.addAll(a2);
                        System.out.println(“a1 list after merge : ” + a1);
            }
}

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