41. Triangle Pattern.

import java.io.*;

class Triangle
{
public static void main(String arg[])
{
InputStreamReader istream = new InputStreamReader(System.in);
BufferedReader read = new BufferedReader(istream);
System.out.println("Enter Triangle Size : ");
int num = 0;
try
{
num = Integer.parseInt(read.readLine());
}
catch (Exception Number)
{
System.out.println("Invalid Number!");
}

for (int i = 1; i <= num; i++)
{
for (int j = 1; j < num - (i - 1); j++)
{
System.out.print(" ");
}

for (int k = 1; k <= i; k++)
{
System.out.print("*");
for (int k1 = 1; k1 < k; k1 += k)
{

System.out.print("*");
}
}

System.out.println();
}
}
}

@java_codings

42. Add two Matrix.
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();
}
}
}

@java_codings

43. Array of Arrays.

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();
}
}
}

@java_codings

44. Array operations.

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);
}
}

@java_codings

45. Array Sort.

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]);
}
}
}

@java_codings

46. Array Sum and Average.

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);
}
}

@java_codings

47. Basic Array.

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] + " ");
}
}
}

@java_codings

48. Create & Display Matrix.

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();
}
}

@java_codings

49. Display Array using for-each loop.

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);
}
}
}

@java_codings

50. Double Matrix.

import java.util.*;
import java.text.DecimalFormat;

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]));
}
}
}

@java_codings

51. Example to Pass Arrays to function.

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);
}
}

@java_codings

52. Find closest value of a number in an Array.

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);
}

}

@java_codings

53. Magic Matrix.

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();
}
}
}
}

@java_codings

54. Matrix Addition.

import java.util.Scanner;

class MatrixAddition {

Scanner scan;
int matrix1[][], matrix2[][], sum[][];
int row, column;

void create() {

scan = new Scanner(System.in);

System.out.println("Matrix Addition");

// First Matrix Creation..
System.out.println("\nEnter number of rows & columns");
row = Integer.parseInt(scan.nextLine());
column = Integer.parseInt(scan.nextLine());

matrix1 = new int[row][column];
matrix2 = new int[row][column];
sum = new int[row][column];

System.out.println("Enter the data for first matrix :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

matrix1[i][j] = scan.nextInt();
}
}

// Second Matrix Creation..
System.out.println("Enter the data for second matrix :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

matrix2[i][j] = scan.nextInt();
}
}
}

void display() {

System.out.println("\nThe First Matrix is :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

System.out.print("\t" + matrix1[i][j]);
}
System.out.println();
}

System.out.println("\n\nThe Second Matrix is :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

System.out.print("\t" + matrix2[i][j]);
}
System.out.println();
}
}

void add() {

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

sum[i][j] = matrix1[i][j] + matrix2[i][j];
}
}

System.out.println("\n\nThe Sum is :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

System.out.print("\t" + sum[i][j]);
}
System.out.println();
}
}
}

class MatrixAdditionExample {

public static void main(String args[]) {

MatrixAddition obj = new MatrixAddition();

obj.create();
obj.display();
obj.add();
}
}

@java_codings

55. Matrix Multiplication.

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");
}
}
}
}

@java_codings

56. Matrix Operations.

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();
}
}
}

@java_codings

57. Matrix Subtraction.

import java.util.Scanner;

class Matrix_Subtraction {

Scanner scan;
int matrix1[][], matrix2[][], sub[][];
int row, column;

void create() {

scan = new Scanner(System.in);

System.out.println("Matrix Subtraction");

// First Matrix Creation..
System.out.println("\nEnter number of rows & columns");
row = Integer.parseInt(scan.nextLine());
column = Integer.parseInt(scan.nextLine());

matrix1 = new int[row][column];
matrix2 = new int[row][column];
sub = new int[row][column];

System.out.println("Enter the data for first matrix :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

matrix1[i][j] = scan.nextInt();
}
}

// Second Matrix Creation..
System.out.println("Enter the data for second matrix :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

matrix2[i][j] = scan.nextInt();
}
}
}

void display() {

System.out.println("\nThe First Matrix is :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

System.out.print("\t" + matrix1[i][j]);
}
System.out.println();
}

System.out.println("\n\nThe Second Matrix is :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

System.out.print("\t" + matrix2[i][j]);
}
System.out.println();
}
}

void sub() {

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

sub[i][j] = matrix1[i][j] - matrix2[i][j];
}
}

System.out.println("\n\nThe Subtraction is :");

for(int i=0; i &lt row; i++) {

for(int j=0; j &lt column; j++) {

System.out.print("\t" + sub[i][j]);
}
System.out.println();
}
}
}

class MatrixSubtractionExample {

public static void main(String args[]) {

Matrix_Subtraction obj = new Matrix_Subtraction();

obj.create();
obj.display();
obj.sub();
}
}

@java_codings