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How to print the Fibonacci series in Ruby using a while loop

okwudili onyejiaku

Overview

A Fibonacci series is a series of numbers in which the next number is the sum of the previous two numbers. The first two numbers are 0 and 1. The third number is the sum of the previous two, and so on.

For example, the following is a Fibonacci series: 0, 1, 1, 2, 3, 5 .... If we see the number 5, it is the sum of the previous two numbers, which are 2 and 3.

In this shot, we'll print the first nth terms of the Fibonacci series in Ruby using while loop.

Syntax

while(counter < n + 1)
    if(counter <= 1)
        nextTerm = c
    else
        nextTerm = firstTerm + secondTerm
        firstTerm = secondTerm
        secondTerm = nextTerm
    end
    counter += 1
end
Syntax to print the Fibonacci Series in Ruby

Parameters

  • counter: This serves as the counter for our loop.
  • n: This represents the nth number of terms of the Fibonacci series we want to get.
  • nextTerm: This represents the next term as the series progresses.
  • firstTerm: This represents the first term of the series as the loop progresses.
  • secondTerm: This represents the second term of the series as the loop progresses.

Return value

It prints the first nth terms of a Fibonacci series.

Example

# create a function to get Fibonacii series
def getFibonacci(n)
  firstTerm = 0
  secondTerm = 1
  nextTerm = 0
  counter = 1
  result = []
  
  puts "The first #{n} terms of Fibonacci series are:-"
  result.push(firstTerm)
  while(counter <= n + 1)
    if(counter <= 1)
        nextTerm = counter
    else
        result.push(nextTerm)
        nextTerm = firstTerm + secondTerm
        firstTerm = secondTerm
        secondTerm = nextTerm
    end
    counter += 1
  end
  # print results 
  puts result.to_s
end 

# create some terms
term1 = 10
term2 = 15
term3 = 50

# get some first nth terms of a Fibonacci series
getFibonacci(term1)
getFibonacci(term2)
getFibonacci(term3)
Example to print the first nth term of a Fibonacci Series in Ruby

Explanation

  • Line 2: We create a function called getFibonacci(), which takes the nth term specified and returns the first nth term of a Fibonacci series.
  • Line 27–29: We create some terms. That is the nth number of terms of a Fibonacci series.
  • Line 32–34: We invoke the function on the terms and print the results to the console.

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