In this tutorial, we will write a Fibonacci Series program in C++. Before that, you should have knowledge of the following topic in C++.

**What is Fibonacci Series?**

Fibonacci series is the series of numbers where the next number is achieved by the addition of the previous two numbers. The initial addition of two numbers is 0 and 1.

**For example**: 0,1,1,2,3,5,8,13….etc.

We will learn two ways to display the Fibonacci series in C.

- upto n terms
- upto certain number.

**1. Fibonacci Series up to n Number of Terms in C++**

The program takes user input for the number terms to be displayed, for loop is used to iterate and print the number. Also, if statements are used for the first two numbers (0, 1).

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | #include <iostream> using namespace std; int main() { int num, term1 = 0, term2 = 1, nextTerm = 0; cout << "Enter the number of terms: "; cin >> num; cout << "Fibonacci Series: "; for (int i = 1; i <= num; ++i) { // if is used for first two numbers in series if (i == 1) { cout << term1 << ", "; continue; } if (i == 2) { cout << term2 << ", "; continue; } nextTerm = term1 + term2; term1 = term2; term2 = nextTerm; cout << nextTerm << ", "; } return 0; } |

**Output:**

`Enter the number of terms: 5`

Fibonacci Series: 0, 1, 1, 2, 3,

**2. C++ Programs to display Fibonacci Series up to a certian number**

In this program, series is displayed up to an entered number. For example, if the user types 50 as an input then the program will display the series of terms present up to 50as shown below.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | #include <iostream> using namespace std; int main() { int num, term1 = 0, term2 = 1, next = 0; cout << "Enter a positive number: "; cin >> num; // for first two numbers cout << "Fibonacci Series: " << term1 << ", " << term2 << ", "; next = term1 + term2; while (next <= num) { cout << next << ", "; term1 = term2; term2 = next; next = term1 + term2; } return 0; } |

**Output:**

`Enter a positive number: 50`

Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34,

You may go through the following: