Fibonacci Series in C, C++, Java & Python – Iterative Code with Explanation & Examples in Short and Simple

C Program

#include
int main() {
  int n, a = 0, b = 1, c;
  scanf("%d", &n);
  for(int i = 0; i < n; i++) {
    printf("%d ", a);
    c = a + b;
    a = b;
    b = c;
  }
  return 0;
}

C Output

Input: 5  
Output: 0 1 1 2 3

C++ Program

#include
using namespace std;
int main() {
  int n, a = 0, b = 1, c;
  cin >> n;
  for(int i = 0; i < n; i++) {
    cout << a << " ";
    c = a + b;
    a = b;
    b = c;
  }
}

C++ Output

Input: 5  
Output: 0 1 1 2 3

JAVA Program

import java.util.*;
class Fibo {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt(), a = 0, b = 1, c;
    for (int i = 0; i < n; i++) {
      System.out.print(a + " ");
      c = a + b;
      a = b;
      b = c;
    }
  }
}

JAVA Output

Input: 5  
Output: 0 1 1 2 3

Python Program

n = int(input())
a, b = 0, 1
for _ in range(n):
  print(a, end=' ')
  a, b = b, a + b

Python Output

Input: 5  
Output: 0 1 1 2 3

In-Depth Learning – Entire Concept in Paragraphs

What is the Fibonacci Series?

The Fibonacci series is a unique sequence in mathematics in which every number is the addition of the two numbers that immediately precede it. It begins with 0 and 1. Then the sequence increases as follows: 0, 1, 1, 2, 3, 5, 8, 13, and so on. This sequence finds application in nature, computer science, and art. In nature, it is seen in the pattern of sunflower seeds, spiral shells, and even galaxies. But in computer science, this same simple pattern is frequently exploited to expose students to the concepts of looping, data dependency, and problem solving with variables.

Why Use Iteration?

While recursion is usually done with Fibonacci, the iterative solution is much faster, particularly when dealing with large input sizes. Recursion relies upon a function call stack that can get extremely deep, in the worst case causing the program to crash or run extremely slowly. Iteration, by contrast, relies upon a straightforward loop that only keeps three variables in mind: one for the current number, one for the last number, and one for their sum. It's memory-efficient, speedy, and perfect for new developers to learn how loops and variables work together.

Example

Assume that we need the first 6 numbers of the Fibonacci series. We start with two initial values: a = 0 and b = 1. On the first iteration, we print 0. Then we calculate the next number as the sum of a + b = 1. We print it and repeat. The series increases as follows:

Begin with 0 and 1

0 + 1 = 1

1 + 1 = 2

1 + 2 = 3

2 + 3 = 5

Therefore the output is: 0 1 1 2 3 5. Each value is a direct progression from the two that precede it, which is a tidy illustration of a real-world dependency chain.

Real-Life Analogy

Suppose you're saving money on a daily basis. On day one, you save ₹0. On day two, ₹1. Starting from the third day, you save an amount which is the sum of what you saved during the previous two days. Hence, on day three you save ₹1 (0+1), on day four ₹2 (1+1), on day five ₹3 (1+2), and so on. This practice of saving money creates a Fibonacci series! It's logical, grows consistently, and shows how actions taken now can be affected by choices made in the past — a valuable lesson in finance as well as logic. 

How the Code Works Logically

The code has a for loop that is executed n times. During each pass, it prints the current value of variable a. Then it computes the next number in the Fibonacci sequence by summing up a and b, and assigns it to c. Then, it reassigns the variables: a gets assigned the previous b, and b gets assigned the next c. It does this repeatedly, building the entire sequence term by term. This sort of loop thinking instructs programmers how to efficiently handle flow, memory, and variable values. It also illustrates the use of recurrence with minimal resources — something that is useful in real-time systems, embedded programming, and coding interviews.

Why Fibonacci Is Important for Programming

Fibonacci sequence is among the earliest introduction to algorithmic thinking. It bridges the gaps between mathematics, patterns, and real-world implementation. It teaches students about recurrence (a value based on earlier values), which later serves as the basis of dynamic programming, memoization, and optimization questions. In technical interviews, this question comes up frequently since it tests your loop usage, variable handling, and pattern understanding. The iterative approach is desirable in interviews when you want to generate a quick, clean, and robust solution.

SEO-Optimized Natural Paragraph for Ranking

If you are looking for a clean, easy method to learn how to generate a Fibonacci series program via iteration, this tutorial is the best fit. The code is in four of the most popular programming languages—C, C++, Java, and Python—and is tailored for students, beginners, and interview preparation for TCS, Wipro, and Infosys companies. With step-by-step explanation, real-life examples, and short working code, this solution makes you aware of how Fibonacci works logically and how to implement it easily. Whether you're preparing for a computer science test or attempting to enhance your competitive programming logic, proficiency in the Fibonacci sequence using iteration is an essential skill—and this page provides you with the complete toolkit to accomplish that.