Kotlin Program to Display Fibonacci Series

In this article, we will understand how to find even sum of Fibonacci series till number N. A Fibonacci series is sequence of numbers formed by the sum of its two previous integers. An even Fibonacci series is all the even numbers of the Fibonacci series.

A Fibonacci series till number N i.e., 10 can look like this ?

0 1 1 2 3 5 8 13 21 34

Below is a demonstration of the same ?

Suppose our input is ?

The input : 15

The desired output would be ?

The Fibonacci series till 15 terms:
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

Algorithm

• Step 1 ? START

• Step 2 ? Declare three variables namely myInput, temp1 and temp2

• Step 3 ? Define the values

• Step 4 ? Use a for loop to iterate through the integers from 1 to N and assign the sum of consequent two numbers as the current Fibonacci number

• Step 5 ? Display the result

• Step 6 ? Stop

Example 1

In this example, we will calculate and display the Fibonacci Series using for loop. First, declare and initialize variables for the input, and two temporary variables. These two variables temp1 and temp2 will store the 1^st and 2^nd values of a Fibonacci.

val myInput = 15
var temp1 = 0
var temp2 = 1

Now, get the Fibonacci using for loop ?

for (i in 1..myInput) {
   print("$temp1 ")
   val sum = temp1 + temp2
   temp1 = temp2
   temp2 = sum
}

Let us now display the Fibonacci Series ?

<div class="execute"></div><div class="code-mirror  language-kotlin" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token keyword">fun</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
   <span class="token keyword">val</span> myInput <span class="token operator">=</span> <span class="token number">15</span>
   <span class="token keyword">var</span> temp1 <span class="token operator">=</span> <span class="token number">0</span>
   <span class="token keyword">var</span> temp2 <span class="token operator">=</span> <span class="token number">1</span>

   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The number is defined as: <span class="token interpolation variable">$myInput</span>"</span><span class="token punctuation">)</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The Fibonacci series till <span class="token interpolation variable">$myInput</span> terms:"</span><span class="token punctuation">)</span>

   <span class="token keyword">for</span> <span class="token punctuation">(</span>i <span class="token keyword">in</span> <span class="token number">1</span><span class="token operator">..</span>myInput<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"<span class="token interpolation variable">$temp1</span> "</span><span class="token punctuation">)</span>
      
      <span class="token keyword">val</span> sum <span class="token operator">=</span> temp1 <span class="token operator">+</span> temp2
      temp1 <span class="token operator">=</span> temp2
      temp2 <span class="token operator">=</span> sum
   <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</div><div class="output-wrapper"><div class="console-close"></div><div class="code-output"></div></div>

Output

The number is defined as: 15
The Fibonacci series till 15 terms:
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 

Example 2

In this example, we will display a Fibonacci Series ?

<div class="execute"></div><div class="code-mirror  language-kotlin" contenteditable="plaintext-only" spellcheck="false" style="outline: none; overflow-wrap: break-word; overflow-y: auto; white-space: pre-wrap;"><span class="token keyword">fun</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
   <span class="token keyword">val</span> myInput <span class="token operator">=</span> <span class="token number">15</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The number is defined as: <span class="token interpolation variable">$myInput</span>"</span><span class="token punctuation">)</span>
   <span class="token function">fibonacciSeries</span><span class="token punctuation">(</span>myInput<span class="token punctuation">)</span>
<span class="token punctuation">}</span>
<span class="token keyword">fun</span> <span class="token function">fibonacciSeries</span><span class="token punctuation">(</span>myInput<span class="token operator">:</span> Int<span class="token punctuation">)</span> <span class="token punctuation">{</span>
   <span class="token keyword">var</span> temp1 <span class="token operator">=</span> <span class="token number">0</span>
   <span class="token keyword">var</span> temp2 <span class="token operator">=</span> <span class="token number">1</span>
   <span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"The fibonacci series till <span class="token interpolation variable">$myInput</span> terms:"</span><span class="token punctuation">)</span>
   
   <span class="token keyword">for</span> <span class="token punctuation">(</span>i <span class="token keyword">in</span> <span class="token number">1</span><span class="token operator">..</span>myInput<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token function">print</span><span class="token punctuation">(</span><span class="token string">"<span class="token interpolation variable">$temp1</span> "</span><span class="token punctuation">)</span>
      <span class="token keyword">val</span> sum <span class="token operator">=</span> temp1 <span class="token operator">+</span> temp2
      temp1 <span class="token operator">=</span> temp2
      temp2 <span class="token operator">=</span> sum
   <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
</div><div class="output-wrapper"><div class="console-close"></div><div class="code-output"></div></div>

Output

The number is defined as: 15
The fibonacci series till 15 terms:
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377