Given an integer N. The task is to find the first N Fibonacci numbers.
Examples :
Input: n = 3
Output: 0 1 1Input: n = 7
Output: 0 1 1 2 3 5 8
Program to print first ‘n’ Fibonacci Numbers using recursion:
Below is the idea to solve the problem:
Use recursion to find nth fibonacci number by calling for n-1 and n-2 and adding their return value. The base case will be if n=0 or n=1 then the fibonacci number will be 0 and 1 respectively.
Follow the below steps to Implement the idea:
- Build a recursive function that takes integer N as a parameter.
- If N = 0 fibonacci number will be 0.
- Else if n = 1 Fibonacci number will be 1.
- Else return value for func(n-1) + func(n-2).
Below is the Implementation of the above approach:
C++
#include <iostream> using namespace std; int fibonacci_numbers( int n) { if (n == 0){ return 0; } else if (n == 1){ return 1; } else { return fibonacci_numbers(n-2) + fibonacci_numbers(n-1); } } int main() { int n = 7; for ( int i = 0; i < n; i++) { cout << fibonacci_numbers(i) << " " ; } return 0; } // This code is contributed by Rupesh Kapse |
Java
/*package whatever //do not write package name here */ import java.io.*; class GFG { public static int fibonacci_numbers( int n) { if (n == 0 ){ return 0 ; } else if (n == 1 ){ return 1 ; } else { return fibonacci_numbers(n- 2 ) + fibonacci_numbers(n- 1 ); } } public static void main (String[] args) { int n = 7 ; for ( int i = 0 ; i < n; i++){ System.out.print(fibonacci_numbers(i)+ " " ); } } } // This code is contributed by Rupesh Kapse |
Python3
# python code to print first n fibonacci numbers def fibonacci_numbers(num): if num = = 0 : return 0 elif num = = 1 : return 1 else : # printing fibonacci numbers return fibonacci_numbers(num - 2 ) + fibonacci_numbers(num - 1 ) n = 7 for i in range ( 0 , n): print (fibonacci_numbers(i), end = " " ) # this code is contributed by gangarajula laxmi |
C#
// C# code to implement the approach using System; class GFG { // Method to calculate the nth fibonacci number public static int fibonacci_numbers( int n) { if (n == 0){ return 0; } else if (n == 1){ return 1; } else { return fibonacci_numbers(n-2) + fibonacci_numbers(n-1); } } // Driver Code public static void Main ( string [] args) { int n = 7; for ( int i = 0; i < n; i++){ // Function call Console.Write(fibonacci_numbers(i)+ " " ); } } } // This code is contributed by phasing17 |
PHP
<?php function fibonacci_numbers( $num ) { if ( $num == 0){ return 0; } elseif ( $num == 1){ return 1; } else { return (fibonacci_numbers( $num -2)+fibonacci_numbers( $num -1)); } } $num =7; for ( $i = 0; $i < $num ; $i ++){ echo fibonacci_numbers( $i ); echo " " ; } // This code is contributed by laxmigangarajula03 ?> |
Javascript
<script> // JavaScript code for the above approach function fibonacci_numbers(n) { if (n == 0) { return 0; } else if (n == 1) { return 1; } else { return fibonacci_numbers(n - 2) + fibonacci_numbers(n - 1); } } let n = 7; for (let i = 0; i < n; i++) { document.write(fibonacci_numbers(i) + " " ); } // This code is contributed by Potta Lokesh </script> |
0 1 1 2 3 5 8
Time Complexity: O(n*2n)
Auxiliary Space: O(n), For recursion call stack.
An iterative approach to print first ‘n’ Fibonacci numbers:
Below is the idea to solve the problem
- Use two variables f1 and f2 and initialize with 0 and 1 respectively because the 1st and 2nd elements of the Fibonacci series are 0 and 1 respectively.
- Iterate from 1 to n-1 and print f2 then store f2 in temp variable and update f2 with f2 + f1 and f1 as f2.
Below is the Implementation of the above approach:
C++
// C++ program to print // first n Fibonacci numbers #include <bits/stdc++.h> using namespace std; // Function to print // first n Fibonacci Numbers void printFibonacciNumbers( int n) { int f1 = 0, f2 = 1, i; if (n < 1) return ; cout << f1 << " " ; for (i = 1; i < n; i++) { cout << f2 << " " ; int next = f1 + f2; f1 = f2; f2 = next; } } // Driver Code int main() { printFibonacciNumbers(7); return 0; } // This code is contributed by rathbhupendra |
C
// C program to print // first n Fibonacci numbers #include <stdio.h> // Function to print // first n Fibonacci Numbers void printFibonacciNumbers( int n) { int f1 = 0, f2 = 1, i; if (n < 1) return ; printf ( "%d " , f1); for (i = 1; i < n; i++) { printf ( "%d " , f2); int next = f1 + f2; f1 = f2; f2 = next; } } // Driver Code int main() { printFibonacciNumbers(7); return 0; } |
Java
// Java program to print // first n Fibonacci Numbers class Test { // Method to print // first n Fibonacci Numbers static void printFibonacciNumbers( int n) { int f1 = 0 , f2 = 1 , i; System.out.print(f1 + " " ); if (n < 1 ) return ; for (i = 1 ; i < n; i++) { System.out.print(f2 + " " ); int next = f1 + f2; f1 = f2; f2 = next; } } // Driver Code public static void main(String[] args) { printFibonacciNumbers( 7 ); } } |
Python3
# Python program to print first n # Fibonacci numbers # Function to print first n # Fibonacci Numbers def printFibonacciNumbers(n): f1 = 0 f2 = 1 if (n < 1 ): return print (f1, end = " " ) for x in range ( 1 , n): print (f2, end = " " ) next = f1 + f2 f1 = f2 f2 = next # Driven code printFibonacciNumbers( 7 ) # This code is contributed by Danish Raza |
C#
// C# program to print // first n Fibonacci Numbers using System; class Test { // Method to print // first n Fibonacci Numbers static void printFibonacciNumbers( int n) { int f1 = 0, f2 = 1, i; if (n < 1) return ; Console.Write(f1 + " " ); for (i = 1; i < n; i++) { Console.Write(f2 + " " ); int next = f1 + f2; f1 = f2; f2 = next; } } // Driver Code public static void Main() { printFibonacciNumbers(7); } } // This code is contributed by nitin mittal. |
PHP
<?php // PHP program to print first // n Fibonacci numbers // Function to print first n // Fibonacci Numbers function printFibonacciNumbers( $n ) { $f1 = 0; $f2 = 1; $i ; if ( $n < 1) return ; echo ( $f1 ); echo ( " " ); for ( $i = 1; $i < $n ; $i ++) { echo ( $f2 ); echo ( " " ); $next = $f1 + $f2 ; $f1 = $f2 ; $f2 = $next ; } } // Driver Code printFibonacciNumbers(7); // This code is contributed by nitin mittal ?> |
Javascript
<script> // Javascript program to print // first n Fibonacci numbers // Function to print // first n Fibonacci Numbers function printFibonacciNumbers(n) { let f1 = 0, f2 = 1, i; if (n < 1) return ; document.write(f1 + " " ); for (i = 1; i < n; i++) { document.write(f2 + " " ); let next = f1 + f2; f1 = f2; f2 = next; } } // Driver Code printFibonacciNumbers(7); // This code is contributed by Mayank Tyagi </script> |
0 1 1 2 3 5 8
Time Complexity: O(n)
Auxiliary Space: O(1)
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