C++ Programming Code Examples C++ > Mathematics Code Examples program to find Fibonacci Series with understanding logic program to find Fibonacci Series with understanding logic 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 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 #include<iostream> using namespace std; int main() { int range, first = 0, second = 1, fibonicci=0; cout << "Enter Range for Terms of Fibonacci Sequence: "; cin >> range; cout << "Fibonicci Series upto " << range << " Terms "<< endl; for ( int c = 0 ; c < range ; c++ ) { if ( c <= 1 ) fibonicci = c; else { fibonicci = first + second; first = second; second = fibonicci; } cout << fibonicci <<" "; } return 0; }