Introduction

    The Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones, usually starting with 0 and 1. It’s a classic problem in programming and mathematics, often used to teach recursion, iteration, and other foundational concepts.

In this blog post, we’ll walk through a Java program that prints the Fibonacci series up to a specified limit.


Code

    
        
        import java.io.*;

        class fibonacci {
            public static void main(String args[]) throws IOException {
                int f1 = 0, f2 = 1, f3 = 0, n;
                DataInputStream s = new DataInputStream(System.in);
        
                // Input the limit for the Fibonacci series
                System.out.println("Enter the limit:");
                n = Integer.parseInt(s.readLine());
        
                // Display the Fibonacci series
                System.out.println("The Fibonacci series is:");
                System.out.println(f1); // Print the first Fibonacci number
                System.out.println(f2); // Print the second Fibonacci number
        
                // Generate the rest of the series up to the limit
                for (int i = 0; i < n - 2; i++) {
                    f3 = f1 + f2;
                    System.out.println(f3);
                    f1 = f2;
                    f2 = f3;
                }
            }
        }


Output


        Enter the limit:
        10
        The Fibonacci series is:
        0
        1
        1
        2
        3
        5
        8
        13
        21
        34


Explanation

1. Initialization:
The program initializes three integer variables: f1 (first Fibonacci number), f2 (second Fibonacci number), and f3 (to store the next number in the series).
2. User Input:
The program prompts the user to enter the limit, n, which defines how many numbers in the Fibonacci series should be printed.
3. Printing the Series:
The first two numbers in the Fibonacci series (0 and 1) are printed directly.
A for loop then iterates n-2 times to generate and print the rest of the series:
The next number, f3, is calculated as the sum of f1 and f2.
The program prints f3, then shifts f1 to f2 and f2 to f3 to prepare for the next iteration.
4. Output:
The program outputs the Fibonacci series up to the specified limit. 

Conclusion

    The Fibonacci series is not only a classic problem in programming but also a fascinating sequence with applications in various fields such as computer science, mathematics, and even nature. This Java program demonstrates how to generate the series iteratively up to a user-defined limit.

By following this simple yet powerful approach, you can quickly produce the Fibonacci sequence for any given number of terms, making it an excellent tool for both beginners and seasoned developers.

Happy coding!