Explanation

This Java code is designed to display the first 10 natural numbers on the console. It achieves this using a fundamental control flow structure called a for loop.

Let's break down the code step by step:

class prog15: This line declares a class named prog15. In Java, all code resides within classes. This class acts as a container for our program.
public static void main(String[] args): This is the main method, which is the entry point for any Java application. When you run this program, the Java Virtual Machine (JVM) looks for and executes the code within this main method.
- public: Means the method can be accessed from anywhere.
- static: Means the method belongs to the class itself, not to any specific object of the class. It can be called without creating an instance of prog15.
- void: Indicates that the method does not return any value.
- main: The name of the method that the JVM recognizes as the starting point.
- String[] args: An array of strings that can be used to pass command-line arguments to the program, though it's not used in this particular example.
System.out.println("First 10 natural numbers:");: This line prints a descriptive string "First 10 natural numbers:" to the console. System.out is an object that represents the standard output stream, and println() is a method that prints the given argument followed by a new line character.
for(int i = 1; i <= 10; i++): This is the core of the program – a for loop. It's designed to execute a block of code repeatedly for a fixed number of times. Let's dissect its three parts:
- int i = 1; (Initialization): This part is executed only once at the beginning of the loop. It declares an integer variable i and initializes it to 1. This variable i will serve as our counter and represent the natural numbers.
- i <= 10; (Condition): This part is evaluated before each iteration. The loop will continue to execute as long as this condition is true. In this case, the loop will run as long as i is less than or equal to 10. Once i becomes 11, the condition 11 <= 10 becomes false, and the loop terminates.
- i++ (Increment/Decrement): This part is executed after each iteration of the loop body. It increments the value of i by 1 (i++ is shorthand for i = i + 1).
System.out.println(i);: This line is inside the for loop's body. It prints the current value of the variable i to the console, followed by a new line. Since this is inside the loop, it will execute repeatedly, printing i's value from 1 up to 10.

In summary, the program first prints a header, then uses a for loop to count from 1 to 10, printing each number on a new line during each iteration.

Algorithm

The algorithm used in this Java code can be described as follows:

Start the Java program execution.
Display the introductory message "First 10 natural numbers:" on the console.
Initialize an integer variable, let's call it i, to 1. This variable will keep track of the current natural number.
Begin Loop: Check if the value of i is less than or equal to 10.
- If i <= 10 is true: a. Print the current value of i to the console, followed by a new line. b. Increment the value of i by 1 (i becomes i + 1). c. Go back to step 4 (re-evaluate the loop condition).
- If i <= 10 is false (meaning i is now 11): a. Exit the loop.
End the program execution.

Explanation

This Java code is designed to display the first 10 natural numbers on the console. It achieves this using a fundamental control flow structure called a for loop.

Let's break down the code step by step:

class prog15: This line declares a class named prog15. In Java, all code resides within classes. This class acts as a container for our program.
public static void main(String[] args): This is the main method, which is the entry point for any Java application. When you run this program, the Java Virtual Machine (JVM) looks for and executes the code within this main method.
- public: Means the method can be accessed from anywhere.
- static: Means the method belongs to the class itself, not to any specific object of the class. It can be called without creating an instance of prog15.
- void: Indicates that the method does not return any value.
- main: The name of the method that the JVM recognizes as the starting point.
- String[] args: An array of strings that can be used to pass command-line arguments to the program, though it's not used in this particular example.
System.out.println("First 10 natural numbers:");: This line prints a descriptive string "First 10 natural numbers:" to the console. System.out is an object that represents the standard output stream, and println() is a method that prints the given argument followed by a new line character.
for(int i = 1; i <= 10; i++): This is the core of the program – a for loop. It's designed to execute a block of code repeatedly for a fixed number of times. Let's dissect its three parts:
- int i = 1; (Initialization): This part is executed only once at the beginning of the loop. It declares an integer variable i and initializes it to 1. This variable i will serve as our counter and represent the natural numbers.
- i <= 10; (Condition): This part is evaluated before each iteration. The loop will continue to execute as long as this condition is true. In this case, the loop will run as long as i is less than or equal to 10. Once i becomes 11, the condition 11 <= 10 becomes false, and the loop terminates.
- i++ (Increment/Decrement): This part is executed after each iteration of the loop body. It increments the value of i by 1 (i++ is shorthand for i = i + 1).
System.out.println(i);: This line is inside the for loop's body. It prints the current value of the variable i to the console, followed by a new line. Since this is inside the loop, it will execute repeatedly, printing i's value from 1 up to 10.

In summary, the program first prints a header, then uses a for loop to count from 1 to 10, printing each number on a new line during each iteration.

Expt 1 - Part 1, Part 2 & Part 3