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C++ program to find Fibonacci Series with understanding logic

13 comments
Fibonacci Series or Sequence
The Fibonacci numbers or Fibonacci series or Fibonacci sequence has first two numbers equal to 1 and 0 and the further each number is consist of the addition of previous two numbers
  1st number = 0
  2nd number = 1
  3rd number = 0+1= 1
  4th number = 1+1= 2
  5th number = 1+2= 3
  And so on.  

 The Fibonacci Sequence can be written as  0,1,1,2,3,5,8,13........



 C++ program to find Fibonacci Series upto given range.This C++ program use simple logic to get the concept of writing code in C++ for Fibonacci Series
  1.     #include<iostream>
  2.     using namespace std;
  3.     int main()
  4.     {
  5.        int range, first = 0, second = 1, fibonicci=0;
  6.        cout << "Enter Range for Terms of Fibonacci Sequence: ";
  7.        cin >> range;
  8.        cout << "Fibonicci Series upto " << range << " Terms "<< endl;
  9.        for ( int c = 0 ; c < range ; c++ )
  10.        {
  11.           if ( c <= 1 )
  12.              fibonicci = c;
  13.           else
  14.           {
  15.              fibonicci = first + second;
  16.              first = second;
  17.              second = fibonicci;
  18.           }
  19.           cout << fibonicci <<" ";
  20.        }
  21.        return 0;
  22.     }

  Fibonacci Series program logic explanation
  • Before writing C++ code we understand that what is Fibonacci Series and in what sequence numbers are occurs
  • After understanding mathematically Fibonacci series completely we thought it in the form of C++ code
  • The Fibonacci series is infinite but we can't make a program that display an infinite output
  • In above program we take input the range in integer upto which Fibonacci series will be displayed
  • For this purpose a for loop has been taken which starts from 0 and terminates less than range for example if Input is 5 then for loop will run from 0 to 4.
  • In for loop if  variable 'c' is  less or equal than 1 in this case if statement  will be executed  and if  'c' is greater than 1 else part will be executed for greater than 1
   e.g if range=2 than only
   if part will run.   let input is equal to 5
   Before loop variables values


   first = 0, second = 1, Fibonacci=0;
   After input range=5
   Values are changing in the following sequence
   in below table  ' c '  representing the for loop iterations
   c    first    second   Fibonacci    Output
  

   0     0         1                 0           0 

   1     0         1                 1           0 1
  
   2     0         1           0+1=1         0 1 1
        
          1          1                1           

   3     1         1           1+1=2         0 1 1 2
     
          1         2                  2

   4    1         2             1+2=3         0 1 1 2 3  its final output
   
         2         3                  3      


     

Image View Of  Program (Click on Image To Enlarge)
Fibonacci series in C++ image Code

Fibonacci Series In C++ Programming
Fibonacci series C++ Code


If you have any queries comment below.

13 comments:

  1. Easier way-(found it out on my own and it works perfectly)
    int a=0,b=1 ;
    for(i=1; i<=n-1; i++)
    {
    cout<<b ;
    b=b+a ;
    a=b-a
    }

    ReplyDelete
  2. Good job! . You can also use i<n instead of your condition statement. it will be same out put. It prints Fibonacci using two variables.

    ReplyDelete
  3. Exellent!!! it will help in my exams, so very thanx to you... i want yor contact oe skype id..

    ReplyDelete
  4. Rudraneel Das..
    There is some minor errors in your code...
    keep it in mind Fibonacci Series starts from ZERO...
    but your logic is better...
    the right code without any error...

    #include
    #include
    void main()
    {
    clrscr();
    int i,n,a=0,b=1;
    cout<<"Enter Range for Fabnocci Series:";
    cin>>n;
    cout<<a<<" ";
    for(i=1;i<n;i++)
    {
    cout<<b<<" ";
    b=b+a;
    a=b-a;
    }
    }

    ReplyDelete
  5. Write the output for the following program: 3
    int main()
    {
    clrscr();
    int a[] = {1,2,3,4,5};
    int l, *k;
    k = &a[0];
    for (l=0;l<5;l++)
    {
    cout<<*k<<”\t”;
    k++;
    }
    return 0;
    }

    ReplyDelete
  6. C++ Program to Generate Fibonacci series

    Fibonacci Series is in the form of 0, 1, 1, 2, 3, 5, 8, 13, 21,...... To find this series we add two previous terms/digits and get next term/number.

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