Program to print first n Fibonacci Numbers | Set 1

Given an integer N. The task is to find the first N Fibonacci numbers.

Examples :

Input: n = 3
Output: 0 1 1

Input: 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 n^th 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>

Output

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>

Output

0 1 1 2 3 5 8 

Time Complexity: O(n) 
Auxiliary Space: O(1)

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