Dear beloved readers, welcome to our website! We hope your visit here brings you valuable insights and meaningful inspiration. Thank you for taking the time to stop by and explore the content we've prepared for you.
------------------------------------------------ 2. Write a Java program to swap two variables.

3. Write a Java program to print a face.

4. Write a Java program to compare three numbers.
NB: Accept all numbers from the keyboard.

5. Write a Java program to check if a character is an alphabet using if-else.

6. Write a Java program to check if a number is even or odd.

7. Write a Java program to find the factorial of a number.

8. What will be the output for the following snippet of code?

```java
public class PrintPattern {
public static void main(String[] args) {
int rows = 5;
for (int i = 1; i <= rows; ++i) {
for (int j = 1; j <= i; ++j) {
System.out.print("* ");
}
System.out.println();
}
}
}
```

9. Write a Java program to check if a character is a vowel or consonant using if and switch statements.

10. Describe what happens if, in `helloWorld.java`, you omit:
a. `main`
b. `String`
c. `HelloWorld`
d. `System.out`

11. Write a Java program to calculate compound interest and simple interest.
NB: compoundInterest = principal \ (Math.pow((1 + rate / 100), time)) - principal;*
simpleInterest = (principal \ rate \* time) / 100;*

12. Write a Java program to calculate the power of a number by accepting the exponent and base from the user.

13. Write a Java program to count vowels and consonants in a string.

14. Write a Java program to reverse an array's elements (from the last element to the first).

15. Write a Java program to print the following patterns.

16. Write the output and explain the reasoning behind each result:

```java
public class PrintPattern {
public static void main(String[] args) {
int x = 14, y = 17;
System.out.println(x | y);
System.out.println(x & y);
System.out.println(x >> 2);
System.out.println(y >> 1);
System.out.println(x << 2);
}
}
```
NB: Explain each output manually.

17. Write a Java program to sum the values of an array and calculate the average value of the array. The array values are [tex]$1, 2, 3, 4, 5, 6, 78, 9, 10$[/tex].

18. Write a Java program to print odd and even numbers from an array element [tex]$\{1, 2, 3, 4, 5, 6, 7, 8, 9, 11\}$[/tex].

19. Write a Java program to find all roots of a quadratic equation.
NB: [tex]$x = \left(-b \pm \sqrt{b^2 - 4ac}\right) / 2a$[/tex]

20. Write a Java program to generate a multiplication table.

Certainly! Let's tackle each Java programming task mentioned step by step:

1. Swap Two Variables in Java:
```java
public class SwapVariables {
public static void main(String[] args) {
int a = 5;
int b = 10;
System.out.println("Before swap: a = " + a + ", b = " + b);
// Swap logic
int temp = a;
a = b;
b = temp;
System.out.println("After swap: a = " + a + ", b = " + b);
}
}
```

2. Print a Face in Java:
```java
public class PrintFace {
public static void main(String[] args) {
System.out.println(" +\"\"\"\"\"+ ");
System.out.println("[| o o |]");
System.out.println(" | ^ | ");
System.out.println(" | '-' | ");
System.out.println(" +-----+ ");
}
}
```

3. Compare Three Numbers:
```java
import java.util.Scanner;

public class CompareNumbers {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Enter three numbers: ");
int num1 = scanner.nextInt();
int num2 = scanner.nextInt();
int num3 = scanner.nextInt();

if (num1 >= num2 && num1 >= num3) {
System.out.println(num1 + " is the largest number.");
} else if (num2 >= num1 && num2 >= num3) {
System.out.println(num2 + " is the largest number.");
} else {
System.out.println(num3 + " is the largest number.");
}
}
}
```

4. Check Alphabet Using if-else:
```java
import java.util.Scanner;

public class CheckAlphabet {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Enter a character: ");
char ch = scanner.next().charAt(0);

if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z')) {
System.out.println(ch + " is an alphabet.");
} else {
System.out.println(ch + " is not an alphabet.");
}
}
}
```

5. Check Even or Odd Number:
```java
import java.util.Scanner;

public class EvenOrOdd {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Enter a number: ");
int number = scanner.nextInt();

if (number % 2 == 0) {
System.out.println(number + " is even.");
} else {
System.out.println(number + " is odd.");
}
}
}
```

6. Find Factorial of a Number:
```java
import java.util.Scanner;

public class Factorial {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Enter a number: ");
int number = scanner.nextInt();
long factorial = 1;

for (int i = 2; i <= number; i++) {
factorial = i;
}
System.out.println("Factorial of " + number + " is " + factorial);
}
}
```

7. Output for the PrintPattern Class:
Given a simple Java code snippet using loops to print a pattern of stars:
```

```

8. Check Vowel or Consonant Using if and switch:
```java
import java.util.Scanner;

public class VowelConsonant {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Enter a character: ");
char ch = scanner.next().charAt(0);

if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z')) {
switch (Character.toLowerCase(ch)) {
case 'a':
case 'e':
case 'i':
case 'o':
case 'u':
System.out.println(ch + " is a vowel.");
break;
default:
System.out.println(ch + " is a consonant.");
}
} else {
System.out.println(ch + " is not an alphabet.");
}
}
}
```

9. Explanation of Java Program ommissions:
a. Omitting 'main': Without the `main` method, the program won’t run as it's the entry point for any Java application.
b. Omitting 'String': The `main` method parameter, `String[] args`, is essential for command-line arguments; removing `String` will lead to a compilation error.
c. Omitting 'HelloWorld': Removing the original class name will cause a compilation error since the file name and the class name must match.
d. Omitting 'System.out': `System.out` is the standard output stream in Java; omitting it will result in errors when trying to print to the console.

These tasks cover a range of basic Java programming skills. Let me know if you need help with anything else!