The document contains a collection of Java programs that demonstrate various mathematical operations and pattern generation, including calculating the area of a rectangle, summing two numbers, calculating factorials, and checking for prime numbers. It also includes programs for generating Fibonacci series, reversing numbers, and performing operations with arrays and 2D arrays, such as finding sums, maximum elements, transposing, and multiplying arrays. Each program includes user input functionality and prints the results to the console.

1. 1
1. Area of Rectangle:
import java.util.Scanner;
public class RectangleArea {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter the length of the rectangle: ");
double length = sc.nextDouble();
System.out.print("Enter the width of the rectangle: ");
double width = sc.nextDouble();
// Calculate the area of the rectangle
double area = length * width;
System.out.println("The area of the rectangle is: " + area);
sc.close();
}
}
2. Addition of Two Numbers.
import java.util.Scanner;
public class Sum
{
public static void main(String[] args)
{
Scanner sc=new Scanner(System.in);
System.out.println("Enter First Number");
int a=sc.nextInt();
System.out.println("Enter Second Number");
int b=sc.nextInt();
int sum=a+b;
System.out.println("Addition is"+sum);
}
}
3. Factorial of Number
import java.util.Scanner;
public class SimpleFactorial
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.print("Enter a number to calculate its factorial: ");
int number = sc.nextInt();
// Calculate the factorial
int factorial = 1;
for (int i = 1; i <= number; i++)
{
factorial *= i;
//factorial=factorial*i;
}
System.out.println("The factorial is: " + factorial);
sc.close();
}

2. 2
}
4. Even or Odd
import java.util.Scanner;
public class EvenOddChecker {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter a number: ");
int number = sc.nextInt();
// Check if the number is even or odd
if (number % 2 == 0) {
System.out.println(number + " is even.");
} else {
System.out.println(number + " is odd.");
}
sc.close();
}
}
5. Fibonacci Series:
import java.util.Scanner;
public class Fibonacci {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter the number of terms: ");
int n = sc.nextInt();
int a = 0, b = 1;
System.out.print("Fibonacci Series: " + a + ", " + b);
for (int i = 2; i < n; i++) {
int next = a + b;
System.out.print(", " + next);
a = b;
b = next;
}
}
}
6. Reverse the number:
import java.util.Scanner;
class Main {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println("Enter the number to reverse:");
int num = sc.nextInt();
int reversed = 0;
System.out.println("Original Number: " + num);
// run loop until num becomes 0
while(num != 0)
{
// get last digit from num
int digit = num % 10;
reversed = reversed * 10 + digit;
// remove the last digit from num
num /= 10;

3. 3
}
System.out.println("Reversed Number: " + reversed);
}
}
7. Armstrong or not:
import java.util.Scanner;
public class ArmstrongNumber {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter a number: ");
int number = sc.nextInt();
int originalNumber = number;
int result = 0;
int n = 0;
// Count the number of digits
while (originalNumber != 0) {
originalNumber /= 10;
++n;
}
originalNumber = number;
// Calculate the sum of the nth power of its digits
while (originalNumber != 0) {
int digit = originalNumber % 10;
result += Math.pow(digit, n);
originalNumber /= 10;
}
if (result == number) {
System.out.println(number + " is an Armstrong number.");
} else {
System.out.println(number + " is not an Armstrong number.");
}
}
}
8. Prime or Not:
import java.util.Scanner;
public class PrimeCheck {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter a number: ");
int number = sc.nextInt();
boolean isPrime = true;
for (int i = 2; i <= number / 2; i++) {
if (number % i == 0) {
isPrime = false;
break;
}
}
if (isPrime) {
System.out.println(number + " is a prime number.");
} else {
System.out.println(number + " is not a prime number.");
}
}
}

4. 4
9. Simple Calculator:
import java.util.Scanner;
public class Calculator {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter first number: ");
double num1 = sc.nextDouble();
System.out.print("Enter second number: ");
double num2 = sc.nextDouble();
System.out.print("Enter an operator (+, -, *, /): ");
char operator = sc.next().charAt(0);
double result;
switch (operator) {
case '+':
result = num1 + num2;
System.out.println("Addition is: " +result);
break;
case '-':
result = num1 - num2;
System.out.println("Subtraction is: " +result);
break;
case '*':
result = num1 * num2;
System.out.println("Multiplication is: " +result);
break;
case '/':
result = num1 / num2;
System.out.println("Devision is: " +result);
break;
default:
System.out.println("Invalid operator!");
return;
}
// System.out.println("Result: " + result);
}
}
10. Swap two Number:
import java.util.Scanner;
public class SwapNumbers {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter the first number: ");
int num1 = sc.nextInt();
System.out.print("Enter the second number: ");
int num2 = sc.nextInt();
// Display numbers before swapping
System.out.println("Before swapping: ");
System.out.println("First number = " + num1);
System.out.println("Second number = " + num2);
// Swap the numbers
int temp = num1;
num1 = num2;
num2 = temp;
// Display numbers after swapping

5. 5
System.out.println("After swapping: ");
System.out.println("First number = " + num1);
System.out.println("Second number = " + num2);
sc.close();
}
}
11. Pyramid Pattern of Star
public class PyramidPattern
{
public static void main(String args[])
{
int i, j, row = 6;
for (i=0; i<row; i++)
{
for (j=row-i; j>1; j--)
{
System.out.print(" ");
}
for (j=0; j<=i; j++ )
{
System.out.print("* ");
}
System.out.println();
} } }
12. Pattern Program:
public class Pattern1
{
public static void main(String args[])
{
int i, j,number, n=7;
for(i=0; i<n; i++)
{
number=1;
for(j=0; j<=i; j++)
{
System.out.print(number+ " ");

6. 6
number++;
}
System.out.println();
} } }
13. Pattern Program:
public class Pattern2
{
public static void main(String[] args)
{
int i, j, k = 1;
for (i = 1; i <= 7; i++)
{
for (j = 1; j< i + 1; j++)
{
System.out.print(k++ + " ");
}
System.out.println();
} } }
14. Pattern Program:
import java.util.*;
public class Pattern5
{
public static void main(String[] args)
{
int i, j, rows;
Scanner sc = new Scanner(System.in);
System.out.print("Enter the number of rows you want to print: ");
rows = sc.nextInt();
for (i = 1; i <= rows; i++)

7. 7
{
for (j = 1; j <= i; j++)
{
System.out.print(i+" ");
}
System.out.println();
} }}
15. Pattern Program:
public class RightAlphabaticPattern
{
public static void main(String[] args)
{
int alphabet = 65; //ASCII value of capital A is 65
for (int i = 0; i <= 8; i++)
{
for (int j = 0; j <= i; j++)
{
System.out.print((char) (alphabet + j) + " ");
}
System.out.println();
}}}
16. Array program
Find the Sum of Array Elements
public class Main {
public static void main(String[] args) {
// Declare and initialize an array of 5 integers
int[] array = {10, 20, 30, 40, 50};
// Calculate the sum of the elements of the array
int sum = 0;
for (int i = 0; i < array.length; i++) {
sum += array[i];
}
// Print the sum of the elements
System.out.println("Sum of the array elements is: " + sum);
}

8. 8
}
Output
Sum of the array elements is: 150
17. Find the Maximum Element in an Array
public class Main {
public static void main(String[] args) {
// Declare and initialize an array of 5 integers
int[] array = {10, 20, 30, 40, 50};
// Find the maximum element in the array
int max = array[0];
for (int i = 1; i < array.length; i++) {
if (array[i] > max) {
max = array[i];
}
}
// Print the maximum element
System.out.println("Maximum element in the array is: " + max);
}
}
Output
Maximum element in the array is: 50
-------------------------------------------X-X-X-X-X-X-X-X-X-X-X
18. Sum of All Elements in a 2D Array
public class Main {
public static void main(String[] args) {
// Declare and initialize a 2D array
int[][] array = {
{1, 2, 3},
{4, 5, 6},
{7, 8, 9}
};
// Calculate the sum of all elements in the 2D array
int sum = 0;
for (int i = 0; i < array.length; i++) {
for (int j = 0; j < array[i].length; j++) {
sum += array[i][j];
}
}
// Print the sum of all elements
System.out.println("Sum of all elements in the 2D array is: " + sum);
}
}
Output
Sum of all elements in the 2D array is: 45

9. 9
19. Transpose of a 2D Array
public class Main {
public static void main(String[] args) {
// Declare and initialize a 2D array
int[][] array = {
{1, 2, 3},
{4, 5, 6},
{7, 8, 9}
};
// Transpose the 2D array
int[][] transpose = new int[array[0].length][array.length];
for (int i = 0; i < array.length; i++) {
for (int j = 0; j < array[i].length; j++) {
transpose[j][i] = array[i][j];
}
}
// Print the transposed array
System.out.println("Transpose of the 2D array is:");
for (int i = 0; i < transpose.length; i++) {
for (int j = 0; j < transpose[i].length; j++) {
System.out.print(transpose[i][j] + " ");
}
System.out.println();
}
}
}
Output
Transpose of the 2D array is:
1 4 7
2 5 8
3 6 9
20. Multiplication of Two 2D Arrays
public class Main {
public static void main(String[] args) {
// Declare and initialize two 2D arrays
int[][] array1 = {
{1, 2, 3},
{4, 5, 6}
};
int[][] array2 = {
{7, 8},
{9, 10},
{11, 12}
};
// Multiply the two 2D arrays
int[][] product = new int[array1.length][array2[0].length];
for (int i = 0; i < array1.length; i++) {
for (int j = 0; j < array2[0].length; j++) {

10. 10
for (int k = 0; k < array1[0].length; k++) {
product[i][j] += array1[i][k] * array2[k][j];
}
}
}
// Print the product of the two arrays
System.out.println("Product of the two 2D arrays is:");
for (int i = 0; i < product.length; i++) {
for (int j = 0; j < product[i].length; j++) {
System.out.print(product[i][j] + " ");
}
System.out.println();
}
}
}
Output
Product of the two 2D arrays is:
58 64
139 154