In this post, we will learn how to display Fibonacci sequences using C++ Programming language. But before that, let’s learn about the Fibonacci sequence.
The Fibonacci sequence is a series of numbers in which the next term is the sum of the previous two terms. The Fibonacci sequence starts with 0 and 1 and goes like this: 0, 1, 1, 2, 3, 5, 8, 13, . . . and so on.
Today, we will calculate the Fibonacci series using a simple for loop statement.
So, without further ado, let’s begin this tutorial.
C++ Program to Display Fibonacci Sequence
// C++ Program to Display Fibonacci Sequence
#include <iostream>
using namespace std;
int main(){
int n, first = 0, second = 1, next_term = 0;
// Asking for input
cout << "Enter the number of terms: ";
cin >> n;
// Displaying fibonacci sequence
cout << "Fibonacci series up to " << n << " terms are: " << endl;
for (int i = first; i <= n; i++){
cout << first << " ";
next_term = first + second;
first = second;
second = next_term;
}
return 0;
}
Output
Enter the number of terms: 15
Fibonacci series up to 15 are:
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610
How Does This Program Work ?
int n, first = 0, second = 1, next_term = 0;
In this program, we have declared four integer data type variables named n, first, second and next_term.
// Asking for input
cout << "Enter the number of terms: ";
cin >> n;
This program asks the user to enter the total number of terms. This value gets stored in the ‘n’ named variable.
// Displaying fibonacci sequence
cout << "Fibonacci series up to " << n << " terms are: " << endl;
for (int i = first; i <= n; i++){
cout << first << " ";
next_term = first + second;
first = second;
second = next_term;
}
Now, we used a for loop to calculate the Fibonacci series. Suppose, the user enters n = 5. Then, accordingly we have:
1st For Loop Iteration: for (int i = 0; i <= 5; i++), here the condition is True. So, the program will print the value of the first variable which is 0 for this case.
- next_term = first + second = 0 + 1 = 1
- first = second = 1
- second = next_term = 1
Now, 2nd For Loop Iteration: for (int i = 1; i <= 5; i++), here the condition is True. So, the loop continues and prints the value of i which is 1 for this iteration.
- next_term = first + second = 1 + 1 = 2
- first = second = 1
- second = next_term = 2
3rd For Loop Iteration: for (int i = 1; i <= 5; i++), here the condition is True. So, the loop will continue and print the value of i which is again 1 for this iteration.
- next_term = first + second = 1 + 2 = 3
- first = second = 2
- second = next_term = 3
4th For Loop Iteration: for (int i = 2; i <= 5; i++), here the condition is True. So, the loop will continue and print the value of i which is 2 for this iteration.
- next_term = first + second = 2 + 3 = 5
- first = second = 3
- second = next_term = 5
5th For Loop Iteration: for (int i = 3; i <= 5; i++), here the condition is True. So, the loop will continue and print the value of i which is 3 for this iteration.
- next_term = first + second = 3 + 5 = 8
- first = second = 5
- second = next_term = 8
6th For Loop Iteration: for (int i = 5; i <= 5; i++), here the condition is True. So, the loop will continue and print the value of i which is 5 for this iteration.
- next_term = first + second = 5 + 8 = 13
- first = second = 8
- second = next_term = 13
7th For Loop Iteration: (int i = 8; i <= 5; i++), here we get i = first = 8 which is greater than n. So, here the condition is False, so the loop terminates.
And we get the Sequence {0, 1, 1, 2, 3, 5}.
Conclusion
I hope after going through this post, you understand how to display a fibonacci sequence using C++ Programming language.
If you have any doubt regarding the post, then feel free to contact us in the comment section. We will be delighted to assist you.
Also Read:
The program example prints 16 terms, not 15. And the first Fibonacci term is 1, not 0.