Fibonacci using Recursion
Fibonacci Series using Recursion in C++
BeginnerTopic: Recursion Programs
C++ Fibonacci using Recursion Program
This program helps you to learn the fundamental structure and syntax of C++ programming.
#include <iostream>
using namespace std;
// Recursive function to calculate Fibonacci number
int fibonacci(int n) {
// Base cases
if (n == 0) {
return 0;
}
if (n == 1) {
return 1;
}
// Recursive case
return fibonacci(n - 1) + fibonacci(n - 2);
}
int main() {
int terms;
cout << "Enter number of terms: ";
cin >> terms;
if (terms < 0) {
cout << "Invalid input." << endl;
return 1;
}
cout << "Fibonacci series:" << endl;
for (int i = 0; i < terms; i++) {
cout << fibonacci(i) << " ";
}
cout << endl;
// Show individual Fibonacci numbers
cout << "\nIndividual Fibonacci numbers:" << endl;
for (int i = 0; i <= 10; i++) {
cout << "F(" << i << ") = " << fibonacci(i) << endl;
}
return 0;
}Output
Enter number of terms: 10 Fibonacci series: 0 1 1 2 3 5 8 13 21 34 Individual Fibonacci numbers: F(0) = 0 F(1) = 1 F(2) = 1 F(3) = 2 F(4) = 3 F(5) = 5 F(6) = 8 F(7) = 13 F(8) = 21 F(9) = 34 F(10) = 55
Understanding Fibonacci using Recursion
Fibonacci: F(n) = F(n-1) + F(n-2). Base cases: F(0) = 0, F(1) = 1. This recursive implementation is inefficient (O(2^n)) due to repeated calculations. Memoization or iterative approach is better for large n. Demonstrates multiple base cases in recursion.
Note: To write and run C++ programs, you need to set up the local environment on your computer. Refer to the complete article Setting up C++ Development Environment. If you do not want to set up the local environment on your computer, you can also use online IDE to write and run your C++ programs.