Below are the set of 19 essential java program for an interview, hope you also referred our pervious post for java program.
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Write a java program to Add two Matrix
package com.onurdesk.arraymatrix.programs;
import java.util.*;
class AddTwoMatrix {
int m, n;
int first[][] = new int[m][n];
int second[][] = new int[m][n];
AddTwoMatrix(int[][] first, int[][] second, int m, int n) {
this.first = first;
this.second = second;
this.m = m;
this.n = n;
}
public static void main(String[] args) {
int m, n, c, d;
Scanner in = new Scanner(System.in);
System.out.println("Enter the number of rows and columns of matrix");
m = in.nextInt();
n = in.nextInt();
int first[][] = new int[m][n];
int second[][] = new int[m][n];
System.out.println("Enter the elements of first matrix");
for (c = 0; c < m; c++) {
for (d = 0; d < n; d++) {
first[c][d] = in.nextInt();
}
}
System.out.println("Enter the elements of second matrix");
for (c = 0; c < m; c++) {
for (d = 0; d < n; d++) {
second[c][d] = in.nextInt();
}
}
System.out.println("\nElements of First matrix is : ");
for (c = 0; c < m; c++) {
for (d = 0; d < n; d++) {
System.out.print(first[c][d] + "\t");
}
System.out.println();
}
System.out.println("\nElements of Second matrix is : ");
for (c = 0; c < m; c++) {
for (d = 0; d < n; d++) {
System.out.print(second[c][d] + "\t");
}
System.out.println();
}
AddTwoMatrix a = new AddTwoMatrix(first, second, m, n);
// call by reference
a.addmatrix(a); // Passing Object
}
// Function for Adding two matrix and storing in third matrix
public void addmatrix(AddTwoMatrix a) {
int c, d;
int sum[][] = new int[a.m][a.n];
for (c = 0; c < a.m; c++) {
for (d = 0; d < a.n; d++) {
sum[c][d] = a.first[c][d] + a.second[c][d];
}
}
System.out.println("\nSum of the two matrices is : ");
for (c = 0; c < a.m; c++) {
for (d = 0; d < a.n; d++) {
System.out.print(sum[c][d] + "\t");
}
System.out.println();
}
}
}
Write a java program of Array of Arrays in java.
package com.onurdesk.arraymatrix.programs;
class ArrayOfArraysAnimalDemo
{
public static void main(String[] args)
{
String[][] animals = {{"DanaDog", "WallyDog", "JessieDog", "AlexisDog", "LuckyDog"}, {"BibsCat", "DoodleCat", "MillieCat", "SimonCat"}, {"ElyFish", "CloieFish", "GoldieFish", "OscarFish", "ZippyFish", "TedFish"}, {"RascalMule", "GeorgeMule", "GracieMule", "MontyMule", "BuckMule", "RosieMule"}};
for (int i = 0; i < animals.length; i++)
{
System.out.print(animals[i][0] + ": ");
for (int j = 1; j < animals[i].length; j++)
{
System.out.print(animals[i][j] + " ");
}
System.out.println();
}
}
}
Write a java program to perform operation on Array.
package com.onurdesk.arraymatrix.programs;
class ArrayOperations
{
public static void main(String[] args)
{
double[] myList = {1.9, 2.9, 3.4, 3.5};
// Print all the array elements
for (int i = 0; i < myList.length; i++)
{
System.out.println(myList[i] + " ");
}
// Summing all elements
double total = 0;
for (int i = 0; i < myList.length; i++)
{
total += myList[i];
}
System.out.println("Total is " + total);
// Finding the largest element
double max = myList[0];
for (int i = 1; i < myList.length; i++)
{
if (myList[i] > max)
max = myList[i];
}
System.out.println("Max is " + max);
}
}
Write a java program to sort an Array.
package com.onurdesk.arraymatrix.programs;
import java.util.Arrays;
class ArraySort
{
// This program is the example of array sorting
public static void main(String[] args)
{
// TODO Auto-generated method stub
// initializing unsorted array
String iArr[] = {"Programming", "Hub", "Alice", "Wonder", "Land"};
// sorting array
Arrays.sort(iArr);
// let us print all the elements available in list
System.out.println("The sorted array is:");
for (int i = 0; i < iArr.length; i++)
{
System.out.println(iArr[i]);
}
}
}
Write a java program to sum and average of Array.
package com.onurdesk.arraymatrix.programs;
import java.io.*;
class ArrayAverage
{
public static void main(String[] args)
{
//define an array
int[] numbers = new int[]{10, 20, 15, 25, 16, 60, 100};
int sum = 0;
for (int i = 0; i < numbers.length; i++)
{
sum = sum + numbers[i];
}
double average = sum / numbers.length;
System.out.println("Sum of array elements is : " + sum);
System.out.println("Average value of array elements is : " + average);
}
}
Write a java program to take elements of array and print the array.
package com.onurdesk.arraymatrix.programs;
import java.util.*;
class ArrayBasic
{
public static void main(String[] args)
{
int[] arr;
int size, i;
Scanner sc = new Scanner(System.in);
System.out.println("Enter size of array");
size = sc.nextInt();
arr = new int[size];
System.out.println("\nEnter array elements");
for (i = 0; i < size; i++)
{
arr[i] = sc.nextInt();
}
System.out.println("\nElements in the Array are : ");
for (i = 0; i < size; i++)
{
System.out.print(arr[i] + " ");
}
}
}
Write a java program to create and display Matrix.
package com.onurdesk.arraymatrix.programs;
import java.util.Scanner;
class Matrix_Create {
Scanner scan;
int matrix[][];
int row, column;
void create() {
scan = new Scanner(System.in);
System.out.println("Matrix Creation");
System.out.println("\nEnter number of rows :");
row = Integer.parseInt(scan.nextLine());
System.out.println("Enter number of columns :");
column = Integer.parseInt(scan.nextLine());
matrix = new int[row][column];
System.out.println("Enter the data :");
for(int i=0; i<row ; i++) {
for(int j=0; j
<column ; j++) {
matrix[i][j] =scan.nextInt();
}
}
}
void display() {
System.out.println("\nThe Matrix is :");
for(int i=0; i <row ; i++) {
for(int j=0; j <column ; j++) {
System.out.print("\t" + matrix[i][j]);
}
System.out.println();
}
}
}
class CreateAndDisplayMatrix {
public static void main(String
args[]) {
Matrix_Create obj=new Matrix_Create();
obj.create();
obj.display();
}
}
Write a java program to create and display Double Matrix.
package com.onurdesk.arraymatrix.programs;
import java.util.*;
import java.text.DecimalFormat;
//like us on facebook : https://facebook.com/onurdesk
class DoubleMatrix
{
public static void main(String[] args)
{
double[][] a;
double[] s;
int row, col, k = 0, i, j;
double sum = 0.0;
DecimalFormat f = new DecimalFormat("##.####");
Scanner sc = new Scanner(System.in);
System.out.println("Enter size of row and column");
row = sc.nextInt();
col = sc.nextInt();
a = new double[row][col];
s = new double[col];
System.out.println("Enter elements of matrix");
for (i = 0; i < row; i++)
{
for (j = 0; j < col; j++)
{
a[i][j] = sc.nextDouble();
}
}
System.out.println("Double Matrix is : ");
for (i = 0; i < row; i++)
{
for (j = 0; j < col; j++)
{
System.out.print(" " + a[i][j]);
}
System.out.println();
}
//sum of the elements of double matrix
for (i = 0; i < col; i++)
{
for (j = 0; j < row; j++)
{
sum = sum + a[j][i];
}
s[k] = sum;
k++;
sum = 0;
}
for (i = 0; i < col; i++)
{
System.out.println("Sum of Column " + (i + 1) + " is : " + f.format(s[i]));
}
}
}
Write a java program to Display array using For Each loop.
package com.onurdesk.arraymatrix.programs;
class DisplayArrayForEach
{
public static void main(String[] args)
{
double[] myList = {1.9, 2.9, 3.4, 3.5};
// Print all the array elements
for (double element : myList)
{
System.out.println(element);
}
}
}
Write a java program to Pass Arrays to function.
package com.onurdesk.arraymatrix.programs;
import java.util.*;
class PassingArraystoFunction
{
public static void main(String[] args)
{
int[] a;
int size;
Scanner sc = new Scanner(System.in);
System.out.println("Enter size of array");
size = sc.nextInt();
a = new int[size];
System.out.println("Enter elements in the array");
for(int i = 0 ;i < size; i++)
{
a[i] = sc.nextInt();
}
System.out.println("The Elements of the array are : ");
for(int i = 0 ;i < size; i++)
{
System.out.print(a[i] + " ");
}
//Passing array to the function
addElements(a, size);
}
public static void addElements(int[] a , int size)
{
int sum = 0;
for(int i = 0; i < size; i++)
{
sum += a[i];
}
System.out.println("\nSum of the elements of arrays is : "+sum);
}
}
Write a java program to find the closest value of a number in an Array.
package com.onurdesk.arraymatrix.programs;
import java.util.*;
class ClosestValue
{
public static void main(String[] args)
{
int a[];
int find;
int closest = 0;
Scanner sc = new Scanner(System.in);
System.out.println("Enter size of array");
int size = sc.nextInt();
a = new int[size];
System.out.println("Enter numbers in array");
for (int i = 0; i < size; i++)
{
a[i] = sc.nextInt();
}
System.out.println("Numbers are : ");
for (int i = 0; i < size; i++)
{
System.out.print(a[i] + " ");
}
System.out.println();
System.out.println("Enter Number to find closest value");
find = sc.nextInt();
int distance = Math.abs(closest - find);
for (int i : a)
{
int distanceI = Math.abs(i - find);
if (distance > distanceI)
{
closest = i;
distance = distanceI;
}
}
System.out.println("Closest Value is : " + closest);
}
}Write a java program for Magic Matrix.
package com.onurdesk.arraymatrix.programs;
import java.io.*;
class MagicMatrix
{
public static void main(String args[]) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Enter the size of the matrix : ");
int n = Integer.parseInt(br.readLine());
if (n > 5)
System.out.println("Enter a number between 1 to 5 ");
else
{
int A[][] = new int[n][n]; // Creating the Magic Matrix
int i, j, k, t;
/*Initializing every cell of the matrix with 0 */
for (i = 0; i < n; i++)
{
for (j = 0; j < n; j++)
{
A[i][j] = 0;
}
}
/* When the size of the matrix is Odd */
if (n % 2 != 0)
{
i = 0;
j = n / 2;
k = 1;
while (k <= n * n)
{
A[i][j] = k++;
i--; // Making one step upward
j++; // Moving one step to the right
if (i < 0 && j > n - 1) // Condition for the top-right corner element
{
i = i + 2;
j--;
}
if (i < 0) // Wrapping around the row if it goes out of boundary
i = n - 1;
if (j > n - 1) // Wrapping around the column if it goes out of boundary
j = 0;
if (A[i][j] > 0) // Condition when the cell is already filled
{
i = i + 2;
j--;
}
}
}
/* When the size of the matrix is even */
else
{
k = 1;
/* Filling the matrix with natural numbers from 1 till n*n */
for (i = 0; i < n; i++)
{
for (j = 0; j < n; j++)
{
A[i][j] = k++;
}
}
j = n - 1;
for (i = 0; i < n / 2; i++)
{
/* swapping corner elements of primary diagonal */
t = A[i][i];
A[i][i] = A[j][j];
A[j][j] = t;
/* swapping corner elements of secondary diagonal */
t = A[i][j];
A[i][j] = A[j][i];
A[j][i] = t;
j--;
}
}
/* Printing the Magic matrix */
System.out.println("The Magic Matrix of size " + n + "x" + n + " is:");
for (i = 0; i < n; i++)
{
for (j = 0; j < n; j++)
{
System.out.print(A[i][j] + "\t");
}
System.out.println();
}
}
}
}
Write a java program to perform Matrix Multiplication.
package com.onurdesk.arraymatrix.programs;
import java.util.Scanner;
class MatrixMultiplication
{
public static void main(String args[])
{
int m, n, p, q, sum = 0, c, d, k;
Scanner in = new Scanner(System.in);
System.out.println("Enter the number of rows and columns of first matrix");
m = in.nextInt();
n = in.nextInt();
int first[][] = new int[m][n];
System.out.println("Enter the elements of first matrix");
for (c = 0; c < m; c++)
{
for (d = 0; d < n; d++)
{
first[c][d] = in.nextInt();
}
}
System.out.println("Enter the number of rows and columns of second matrix");
p = in.nextInt();
q = in.nextInt();
if (n != p)
System.out.println("Matrices with entered orders can't be multiplied with each other.");
else
{
int second[][] = new int[p][q];
int multiply[][] = new int[m][q];
System.out.println("Enter the elements of second matrix");
for (c = 0; c < p; c++)
{
for (d = 0; d < q; d++)
{
second[c][d] = in.nextInt();
}
}
for (c = 0; c < m; c++)
{
for (d = 0; d < q; d++)
{
for (k = 0; k < p; k++)
{
sum = sum + first[c][k] * second[k][d];
}
multiply[c][d] = sum;
sum = 0;
}
}
System.out.println("Product of entered matrices:-");
for (c = 0; c < m; c++)
{
for (d = 0; d < q; d++)
{
System.out.print(multiply[c][d] + "\t");
}
System.out.print("\n");
}
}
}
}
Writ a java program to perform operations on Matrix.
package com.onurdesk.arraymatrix.programs;
import java.util.Scanner;
public class Matrices {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter number of rows: ");
int rows = scanner.nextInt();
System.out.print("Enter number of columns: ");
int columns = scanner.nextInt();
System.out.println();
System.out.println("Enter first matrix");
int[][] a = readMatrix(rows, columns);
System.out.println();
System.out.println("Enter second matrix");
int[][] b = readMatrix(rows, columns);
int[][] sum = add(a, b);
int[][] difference1 = subtract(a, b);
int[][] difference2 = subtract(b, a);
System.out.println();
System.out.println("A + B =");
printMatrix(sum);
System.out.println();
System.out.println("A - B =");
printMatrix(difference1);
System.out.println();
System.out.println("B - A =");
printMatrix(difference2);
}
public static int[][] readMatrix(int rows, int columns) {
int[][] result = new int[rows][columns];
Scanner s = new Scanner(System.in);
for (int i = 0; i < rows; i++) {
for (int j = 0; j < columns; j++) {
result[i][j] = s.nextInt();
}
}
return result;
}
public static int[][] add(int[][] a, int[][] b) {
int rows = a.length;
int columns = a[0].length;
int[][] result = new int[rows][columns];
for (int i = 0; i < rows; i++) {
for (int j = 0; j < columns; j++) {
result[i][j] = a[i][j] + b[i][j];
}
}
return result;
}
public static int[][] subtract(int[][] a, int[][] b) {
int rows = a.length;
int columns = a[0].length;
int[][] result = new int[rows][columns];
for (int i = 0; i < rows; i++) {
for (int j = 0; j < columns; j++) {
result[i][j] = a[i][j] - b[i][j];
}
}
return result;
}
public static void printMatrix(int[][] matrix) {
int rows = matrix.length;
int columns = matrix[0].length;
for (int i = 0; i < rows; i++) {
for (int j = 0; j < columns; j++) {
System.out.print(matrix[i][j] + " ");
}
System.out.println();
}
}
}
Writ a java program for Merge two array.
package com.onurdesk.arraymatrix.programs;
class MergeArrayDemo
{
public static void main(String args[])
{
Integer a[]={1,2,3,4};
Integer b[]={5,6,7,0};
Integer[] both = concat(a, b);
System.out.print("\nFirst Array : ");
for(int i=0;i<a.length;i++)
{
System.out.print(a[i]+"\t");
}
System.out.print("\nSecond Array : ");
for(int i=0;i<b.length;i++)
{
System.out.print(b[i]+"\t");
}
System.out.print("\nMerged Array : ");
for(int i=0;i<both.length;i++)
{
System.out.print(both[i]+"\t");
}
}
public static Integer[] concat(Integer[] a, Integer[] b)
{
int aLen = a.length;
int bLen = b.length;
Integer[] c= new Integer[aLen+bLen];
System.arraycopy(a, 0, c, 0, aLen);
System.arraycopy(b, 0, c, aLen, bLen);
return c;
}
}
Write a java program to find middle value of array.
package com.onurdesk.arraymatrix.programs;
import java.util.*;
class MiddleValue
{
public static void main(String args[])
{
int[] a;
int i, j, n, sum = 0, swap, size;
double t;
Scanner sc = new Scanner(System.in);
System.out.println("Enter size of array");
size = sc.nextInt();
a = new int[size];
System.out.println("Enter numbers ");
for (i = 0; i < size; i++)
{
a[i] = sc.nextInt();
}
System.out.println("Numbers are : ");
for (i = 0; i < size; i++)
{
System.out.print(a[i] + " ");
}
//Sorting
for (i = 0; i < (size - 1); i++)
{
for (j = 0; j < (size - i - 1); j++)
{
if (a[j] > a[j + 1])
{
swap = a[j];
a[j] = a[j + 1];
a[j + 1] = swap;
}
}
}
System.out.println("\nNumbers in sorted order : ");
for (i = 0; i < size; i++)
{
System.out.print(a[i] + " ");
}
//Finding the Middle Value
if (size % 2 == 0)
{
n = (size + 1) / 2;
t = (a[n] + a[n - 1]) / 2.0;
System.out.println("\nMiddle Value is : " + t);
}
else
{
System.out.println("\nMiddle Value is : " + a[size / 2]);
}
}
}
Write a java program for Mirror Matrix.
package com.onurdesk.arraymatrix.programs;
import java.util.*;
class MirrorMatrix
{
public static void main(String[] args)
{
int row, column;
Scanner in = new Scanner(System.in);
System.out.print("Enter number of rows for matrix :");
row = in.nextInt();
System.out.print("Enter number of rows for matrix :");
column = in.nextInt();
int matrix[][] = new int[row][column];
System.out.println("Enter matrix : ");
for (int i = 0; i < row; i++)
{
for (int j = 0; j < column; j++)
{
matrix[i][j] = in.nextInt();
}
}
System.out.println("Mirror matrix : ");
for (int i = 0; i < row; i++)
{
for (int j = column - 1; j >= 0; j--)
{
System.out.print(matrix[i][j] + "\t");
}
System.out.println("");
}
}
}
Write a java program to find a Missing number in an array.
class MissingNumberArray
{
public static int count = 0;
public static int position = 0;
public static boolean flag = false;
public static void main(String[] args)
{
int a[] = {0, 1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 20, 21, 23};
findMissingNumbers(a, position);
}
private static void findMissingNumbers(int a[], int position)
{
if (position == a.length - 1)
return;
for (; position < a[a.length - 1]; position++)
{
if ((a[position] - count) != position)
{
System.out.println("Missing Number: " + (position + count));
flag = true;
count++;
break;
}
}
if (flag)
{
flag = false;
findMissingNumbers(a, position);
}
}
}
Write a java program for Multidimensional Array.
package com.onurdesk.arraymatrix.programs;
class MultiDimArrayExample
{
public static void main(String[] args)
{
String[][] names = {{"Mr. ", "Mrs. ", "Ms. "}, {"Smith", "Jones"}};
// Mr. Smith
System.out.println(names[0][0] + names[1][0]);
// Ms. Jones
System.out.println(names[0][2] + names[1][1]);
}
}
