Expt 1 - Part 1, Part 2 & Part 3

Import Scanner: The line import java.util.Scanner; brings in the Scanner class, which is part of Java's utility library. This class is essential for reading input from the user, such as numbers or text, from the console.

Class Definition: class prog8{ ... } defines a class named prog8. In Java, all code resides within classes. This class acts as a container for our program's logic.

Main Method: public static void main(String args[]){ ... } is the entry point of any Java application. When you run this program, the code inside the main method is executed first.

• public: Means the method is accessible from anywhere.
• static: Means the method belongs to the class itself, not to any specific object of the class, and can be called without creating an instance of prog8.
• void: Indicates that the method does not return any value.
• String args[]: Allows command-line arguments to be passed to the program, though they are not used in this specific code.

Creating a Scanner Object: Scanner input = new Scanner(System.in); creates an object of the Scanner class. This object, named input, is configured to read data from System.in, which represents the standard input stream (typically your keyboard).

Prompting for Input (Number a):

• System.out.print("Enter Number a: "); displays the message "Enter Number a: " on the console, prompting the user to enter the first number. System.out.print does not add a new line after the message, so the user's input will appear on the same line.
• int a = input.nextInt(); reads the integer value typed by the user from the console and stores it in an integer variable named a.

Prompting for Input (Number b): This process is repeated for the second number:

• System.out.print("Enter Number b: "); prompts the user for the second number.
• int b = input.nextInt(); reads the integer and stores it in an integer variable named b.

Swapping the Numbers (Using a Temporary Variable): This is the core logic of the program. To swap two numbers, we need a third, temporary variable to hold one of the values during the exchange. Imagine you have two full glasses of different liquids and want to swap their contents; you'd need a third empty glass to temporarily hold one liquid.

• int temp = a;: A new integer variable temp is declared and initialized with the current value of a. At this point, temp holds a's original value.
• a = b;: The value of b is assigned to a. Now, a holds b's original value. The original value of a is safe in temp.
• b = temp;: The value stored in temp (which was a's original value) is assigned to b. Now, b holds a's original value. After these three steps, the values of a and b have been successfully swapped.

Displaying Results: System.out.println("After swapping\na: " + a + "\nb: " + b); prints the values of a and b after the swap.

• System.out.println() prints the string and then moves to a new line.
• \n is an escape sequence that represents a new line character, ensuring "a:" and "b:" appear on separate lines for better readability.
• The + operator is used here for string concatenation, joining the literal strings with the current values of variables a and b.

Closing the Scanner: input.close(); is an important step that closes the Scanner object. This releases system resources associated with the input stream, preventing potential resource leaks, especially in larger applications.