1. WAP where int []arary= {1,2,3,4,5,6,7,8,9,10} leftRotateArray(array,3) and output should be {4,5,6,7,8,9,10,1,2,3} and rightRotateArray (array,3) output should be {8,9,10,1,2,3,4,5,6,7}
Answer:
import java.util.Arrays;
public class ArrayRotate {
// Initialize array
public static int[] arr = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
// n determine the number of times an array should be rotated.
public static int n = 3;
public static void main(String[] args) {
rightRotation();
leftRotation();
}
public static void rightRotation() {
// Displays original array
System.out.println("Original array: ");
for (int i = 0; i < arr.length; i++) {
System.out.print(arr[i] + " ");
}
// Rotate the given array by n times toward right
for (int i = 0; i < n; i++) {
int j, last;
// Stores the last element of array
last = arr[arr.length - 1];
for (j = arr.length - 1; j > 0; j--) {
// Shift element of array by one
arr[j] = arr[j - 1];
}
// Last element of array will be added to the start of array.
arr[0] = last;
}
System.out.println();
// Displays resulting array after rotation
System.out.println("Array after right rotation: ");
for (int i = 0; i < arr.length; i++) {
System.out.print(arr[i] + " ");
}
}
public static void leftRotation() {
Arrays.sort(arr);
// Rotate the given array by n times toward left
for (int i = 0; i < n; i++) {
int j, first;
// Stores the first element of the array
first = arr[0];
for (j = 0; j < arr.length - 1; j++) {
// Shift element of array by one
arr[j] = arr[j + 1];
}
// First element of array will be added to the end
arr[j] = first;
}
System.out.println();
// Displays resulting array after rotation
System.out.println("Array after left rotation: ");
for (int i = 0; i < arr.length; i++) {
System.out.print(arr[i] + " ");
}
}
}
Output:
Original array:
1 2 3 4 5 6 7 8 9 10
Array after right rotation:
8 9 10 1 2 3 4 5 6 7
Array after left rotation:
4 5 6 7 8 9 10 1 2 3
2. An Array of numbers given. .Find the largest two number and print it.
Answer:
import java.util.Scanner;
public class largest_and_second
{
public static void main (String[] args)
{
Scanner scn = new Scanner (System.in);
System.out.print("Enter no. of elements you want in array:");
int n = scn.nextInt();
int array[] = new int[n];
System.out.println("Enter all the elements:");
for (int i = 0; i < array.length; i++)
{
array[i] = scn.nextInt();
}
int largest1, largest2, temp;
largest1 = array[0];
largest2 = array[1];
if (largest1 < largest2)
{
temp = largest1;
largest1 = largest2;
largest2 = temp;
}
for (int i = 2; i < array.length; i++)
{
if (array[i] > largest1)
{
largest2 = largest1;
largest1 = array[i];
}
else if (array[i] > largest2 && array[i] != largest1)
{
largest2 = array[i];
}
}
System.out.println ("The First largest is " + largest1);
System.out.println ("The Second largest is " + largest2);
}
}
Output:
Enter no. of elements you want in array:5
Enter all the elements:
1
5
4
8
7
The First largest is 8
The Second largest is 7
3. How to convert array into Arraylist?
Answer:
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
public class Tester {
public static void main(String args[]) {
String[] array = {"a", "b", "c", "d", "e"};
//Method 1
List<String> list = Arrays.asList(array);
System.out.println(list);
//Method 2
List<String> list1 = new ArrayList<String>();
Collections.addAll(list1, array);
System.out.println(list1);
//Method 3
List<String> list2 = new ArrayList<String>();
for(String text:array) {
list2.add(text);
}
System.out.println(list2);
}
}
Output:
[a, b, c, d, e]
[a, b, c, d, e]
[a, b, c, d, e]
4. Given an array int a[]=int a{1,2,2,3,4,4,5,5,6,7} find duplicate and store in different array.
Answer:
import java.util.ArrayList;
public class FindDuplicateAndStoreInArray {
public static void main(String[] args) {
// Initialize array
int[] arr = new int[] { 1,2,2,3,4,4,5,5,6,7};
// Creating an ArrayList
ArrayList<Integer> arrlist = new ArrayList<>();
System.out.println("Duplicate elements in given array: ");
// Searches for duplicate element
for (int i = 0; i < arr.length; i++) {
for (int j = i + 1; j < arr.length; j++) {
if (arr[i] == arr[j]) {
System.out.println(arr[j]);
// Storing duplicate elements in an arrayList
arrlist.add(arr[j]);
}
}
}
// Converting ArrayList to an Array
Integer[] arr1 = new Integer[arrlist.size()];
arr1 = arrlist.toArray(arr1);
for (Integer x : arr1)
System.out.print(x + " ");
}
}
Output:
Duplicate elements in given array:
2
4
5
2 4 5
5. Find duplicate integer from an array.
Answer:
class RepeatElement
{
void printRepeating(int arr[], int size)
{
int i, j;
System.out.println("Repeated Elements are :");
for (i = 0; i < size; i++)
{
for (j = i + 1; j < size; j++)
{
if (arr[i] == arr[j])
System.out.print(arr[i] + " ");
}
}
}
public static void main(String[] args)
{
RepeatElement repeat = new RepeatElement();
int arr[] = {4, 2, 4, 5, 2, 3, 1};
int arr_size = arr.length;
repeat.printRepeating(arr, arr_size);
}
}
Output:
Repeating elements are 4 2
6. Find duplicate and store in an array and find unique and store in a separate array.
Answer:
import java.util.ArrayList;
public class FindDuplicateAndStoreInArray {
// Initialize array
public static int[] arr = new int[] { 1, 2, 2, 3, 4, 4, 5, 5, 6, 7 };
public static void main(String[] args) {
findDuplicate();
findUnique();
}
public static void findDuplicate() {
// Creating an ArrayList
ArrayList<Integer> arrlist = new ArrayList<>();
System.out.println("Duplicate elements in given array: ");
// Searches for duplicate element
for (int i = 0; i < arr.length; i++) {
for (int j = i + 1; j < arr.length; j++) {
if (arr[i] == arr[j]) {
System.out.println(arr[j]);
// Storing duplicate elements in an arrayList
arrlist.add(arr[j]);
}
}
}
// Converting ArrayList to an Array
Integer[] arr1 = new Integer[arrlist.size()];
arr1 = arrlist.toArray(arr1);
System.out.print("Array Of Duplicate Elements:");
for (Integer x : arr1)
System.out.print(+x + " ");
}
public static void findUnique() {
// Creating an ArrayList
ArrayList<Integer> arrlist1 = new ArrayList<>();
System.out.println("");
System.out.println("Unique elements in given array: ");
// Searches for Unique elements
int count = 0, flag = 0;
for (int i = 0; i < arr.length; i++) {
for (int j = 0; j < arr.length; j++) {
if (i != j) {
if (arr[i] != arr[j]) {
flag = 1;
} else {
flag = 0;
break;
}
}
}
if (flag == 1) {
count++;
System.out.println(arr[i]);
arrlist1.add(arr[i]);
}
}
// Converting ArrayList to an Array
Integer[] arr2 = new Integer[arrlist1.size()];
arr2 = arrlist1.toArray(arr2);
System.out.print("Array Of Unique Elements:");
for (Integer y : arr2)
System.out.print(+y + " ");
}
}
Output:
Duplicate elements in given array:
2
4
5
Array Of Duplicate Elements:2 4 5
Unique elements in given array:
1
3
6
7
Array Of Unique Elements:1 3 6 7
7. Write a Java program for accessing all the elements of the two dimensional array int[][] a = {{5,2,9},{4,6,8}}; using for loop?
Answer:
import java.util.Arrays;
public class Access2DArray {
public static void main(String args[]) {
// initializing two dimensional array as literal
String[][] names = { { "John", "Smith" }, { "Javin", "Paul" }, { "James", "Gosling" }, }; // how to initialize two dimensional array in Java
// using for loop
int[][] a = { { 5, 2, 9 }, { 4, 6, 8 }, };
// how to print
System.out.println("Using For Loop");
for (int i = 0; i < a.length; ++i) {
for (int j = 0; j < a[i].length; ++j) {
System.out.print(a[i][j] + "\t");
}
System.out.println("\n");
}
System.out.println("Using For each Loop");
// now let's print a two dimensional array in Java
for (int[] a1 : a) {
for (int i : a1) {
System.out.print(i + "\t");
}
System.out.println("\n");
}
// printing 2D array using Arrays.deepToString() method
System.out.println("Another way to print 2D arrays");
System.out.println(Arrays.deepToString(a));
}
}
Output:
Using For Loop
5 2 9
4 6 8
Using For each Loop
5 2 9
4 6 8
Another way to print 2D arrays
[[5, 2, 9], [4, 6, 8]]
8. Write a Java program for sorting an array?
Answer:
import java.util.Scanner;
public class Ascending _Order
{
public static void main(String[] args)
{
int n, temp;
Scanner s = new Scanner(System.in);
System.out.print("Enter no. of elements you want in array:");
n = s.nextInt();
int a[] = new int[n];
System.out.println("Enter all the elements:");
for (int i = 0; i < n; i++)
{
a[i] = s.nextInt();
}
for (int i = 0; i < n; i++)
{
for (int j = i + 1; j < n; j++)
{
if (a[i] > a[j])
{
temp = a[i];
a[i] = a[j];
a[j] = temp;
}
}
}
System.out.print("Ascending Order:");
for (int i = 0; i < n - 1; i++)
{
System.out.print(a[i] + ",");
}
System.out.print(a[n - 1]);
}
}
Output:
Enter no. of elements you want in array:5
Enter all the elements:
4
3
2
6
1
Ascending Order:1,2,3,4,6
9. Write a Java program to create an integer array int[] a = {9,3,6,8,4,7} and print the elements of the array in reverse?
Answer:
public class ReverseArray {
public static void main(String[] args) {
//Initialize array
int [] arr = new int [] {9,3,6,8,4,7};
System.out.println("Original array: ");
for (int i = 0; i < arr.length; i++) {
System.out.print(arr[i] + " ");
}
System.out.println();
System.out.println("Array in reverse order: ");
//Loop through the array in reverse order
for (int i = arr.length-1; i >= 0; i--) {
System.out.print(arr[i] + " ");
}
}
}
Output:
Original array:
9 3 6 8 4 7
Array in reverse order:
7 4 8 6 3 9
10. Write a Java program to print alternative elements in a String array String[] a = {“One”,”Two”,”Three”,”Four”} ?
Answer:
public class AlternateElementsInStringArray {
public static void main(String[] args) {
String[] a = new String[] { "One", "Two", "Three", "Four" };
for (int i = 0; i < a.length; i = i + 2) {
System.out.println(a[i]);
}
}
}
Output:
One
Three
11. Write a Java program to find the greatest number in an integer array int[] a = {9,3,6,4,8,5} ?
Answer:
public class FindBiggestSmallestNumber {
public static void main(String[] args) {
int numbers[] = new int[]{9,3,6,4,8,5};
int smallest = numbers[0];
int biggest = numbers[0];
for(int i=1; i< numbers.length; i++)
{
if(numbers[i] > biggest)
biggest = numbers[i];
else if (numbers[i] < smallest)
smallest = numbers[i];
}
System.out.println("Largest Number is : " + biggest);
//System.out.println("Smallest Number is : " + smallest);
}
}
Output:
Largest Number is : 9
12. Write a Java program to find the Smallest number in an integer array int[] a = {9,3,6,4,8,5} ?
Answer:
public class FindBiggestSmallestNumber {
public static void main(String[] args) {
int numbers[] = new int[]{9,3,6,4,8,5};
int smallest = numbers[0];
int biggest = numbers[0];
for(int i=1; i< numbers.length; i++)
{
if(numbers[i] > biggest)
biggest = numbers[i];
else if (numbers[i] < smallest)
smallest = numbers[i];
}
//System.out.println("Largest Number is : " + biggest);
System.out.println("Smallest Number is : " + smallest);
}
}
Output:
Smallest Number is : 3
13. How to find missing number in an Array?
Answer:
public class MissingNumber {
public static void main(String[] args) {
int[] arr1 = { 7, 5, 6, 1, 4, 2 };
System.out.println("Missing number from array arr1: " + missingNumber(arr1));
int[] arr2 = { 5, 3, 1, 2 };
System.out.println("Missing number from array arr2: " + missingNumber(arr2));
}
public static int missingNumber(int[] arr) {
int n = arr.length + 1;
int sum = n * (n + 1) / 2;
int restSum = 0;
for (int i = 0; i < arr.length; i++) {
restSum += arr[i];
}
int missingNumber = sum - restSum;
return missingNumber;
}
}
Output:
Missing number from array arr1: 3
Missing number from array arr2: 4
14. Write a Java program to demonstrate creating an Array?
Answer:
Syntax to Declare an Array in Java
dataType[] arr; (or)
dataType []arr; (or)
dataType arr[];
Instantiation of an Array in Java
arrayRefVar=new datatype[size];
We can declare, instantiate and initialize the java array together by:
int a[]={33,3,4,5};//declaration, instantiation and initialization
15. Write a Java program to demonstrate creating Multidimensional array?
Answer:
Syntax to Declare Multidimensional Array in Java
dataType[][] arrayRefVar; (or)
dataType [][]arrayRefVar; (or)
dataType arrayRefVar[][]; (or)
dataType []arrayRefVar[];
Example to instantiate Multidimensional Array in Java
int[][] arr=new int[3][3];//3 row and 3 column
Example to initialize Multidimensional Array in Java
arr[0][0]=1;
arr[0][1]=2;
arr[0][2]=3;
arr[1][0]=4;
arr[1][1]=5;
arr[1][2]=6;
arr[2][0]=7;
arr[2][1]=8;
arr[2][2]=9;
16. Write a Java program to add two matrix?
Answer:
public class MatrixAdditionExample{
public static void main(String args[]){
//creating two matrices
int a[][]={{1,3,4},{2,4,3},{3,4,5}};
int b[][]={{1,3,4},{2,4,3},{1,2,4}};
//creating another matrix to store the sum of two matrices
int c[][]=new int[3][3]; //3 rows and 3 columns
//adding and printing addition of 2 matrices
for(int i=0;i<3;i++){
for(int j=0;j<3;j++){
c[i][j]=a[i][j]+b[i][j]; //use - for subtraction
System.out.print(c[i][j]+" ");
}
System.out.println();//new line
}
}}
Output:
2 6 8
4 8 6
4 6 9
17. Write a Java program to multiply two matrix?
Answer:
public class MatrixMultiplicationExample{
public static void main(String args[]){
//creating two matrices
int a[][]={{1,1,1},{2,2,2},{3,3,3}};
int b[][]={{1,1,1},{2,2,2},{3,3,3}};
//creating another matrix to store the multiplication of two matrices
int c[][]=new int[3][3]; //3 rows and 3 columns
//multiplying and printing multiplication of 2 matrices
for(int i=0;i<3;i++){
for(int j=0;j<3;j++){
c[i][j]=0;
for(int k=0;k<3;k++)
{
c[i][j]+=a[i][k]*b[k][j];
}//end of k loop
System.out.print(c[i][j]+" "); //printing matrix element
}//end of j loop
System.out.println();//new line
}
}}
Output:
6 6 6
12 12 12
18 18 18
18. Write a Java program to get the transpose of matrix?
Answer:
public class MatrixTransposeExample{
public static void main(String args[]){
//creating a matrix
int original[][]={{1,3,4},{2,4,3},{3,4,5}};
//creating another matrix to store transpose of a matrix
int transpose[][]=new int[3][3]; //3 rows and 3 columns
//Code to transpose a matrix
for(int i=0;i<3;i++){
for(int j=0;j<3;j++){
transpose[i][j]=original[j][i];
}
}
System.out.println("Printing Matrix without transpose:");
for(int i=0;i<3;i++){
for(int j=0;j<3;j++){
System.out.print(original[i][j]+" ");
}
System.out.println();//new line
}
System.out.println("Printing Matrix After Transpose:");
for(int i=0;i<3;i++){
for(int j=0;j<3;j++){
System.out.print(transpose[i][j]+" ");
}
System.out.println();//new line
}
}}
Output:
Printing Matrix without transpose:
1 3 4
2 4 3
3 4 5
Printing Matrix After Transpose:
1 2 3
3 4 4
4 3 5
19. Write a Java program for printing the Multiplication table?
Answer:
import java.util.Scanner;
class MultiplicationTable
{
public static void main(String args[])
{
int n, c;
System.out.println("Enter an integer to print it's multiplication table");
Scanner in = new Scanner(System.in);
n = in.nextInt();
System.out.println("Multiplication table of " + n);
for (c = 1; c <= 10; c++)
System.out.println(n + "*" + c + " = " + (n*c));
}
}
Output:
Enter an integer to print it's multiplication table
9
Multiplication table of 9
9*1 = 9
9*2 = 18
9*3 = 27
9*4 = 36
9*5 = 45
9*6 = 54
9*7 = 63
9*8 = 72
9*9 = 81
9*10 = 90
20. Write a Java program for pascle triangle?
Answer:
public class PascalsTriangle {
static int factorial(int n) {
int f;
for(f = 1; n > 1; n--){
f *= n;
}
return f;
}
static int ncr(int n,int r) {
return factorial(n) / ( factorial(n-r) * factorial(r) );
}
public static void main(String args[]){
System.out.println();
int n, i, j;
n = 5;
for(i = 0; i <= n; i++) {
for(j = 0; j <= n-i; j++){
System.out.print(" ");
}
for(j = 0; j <= i; j++){
System.out.print(" "+ncr(i, j));
}
System.out.println();
}
}
}
Output:
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
1 5 10 10 5 1
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