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:**

JimThe program example prints 16 terms, not 15. And the first Fibonacci term is 1, not 0.