Example: Fibonacci Series - Iterative in C++

C
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C#
Java
Python
PHP
// Fibonacci Series - Iterative
#include <iostream>
using namespace std;

int main() {
    int n;
    cout << "Enter the number of terms: ";
    cin >> n;

    int t1 = 0, t2 = 1; // Initialize the first two terms
    int nextTerm = 0;

    cout << "Fibonacci Series: ";

    // Step 1: Handle cases for n = 1 or n = 2
    if (n == 0) {
        cout << "No terms to display." << endl;
        return 0;
    } else if (n == 1) {
        cout << t1 << endl;
        return 0;
    } else {
        // Step 2: Print the first two terms
        cout << t1 << ", " << t2;
    }

    // Step 3: Calculate and print subsequent terms
    for (int i = 3; i <= n; ++i) {
        nextTerm = t1 + t2;
        cout << ", " << nextTerm;
        t1 = t2; // Update t1 to the previous t2
        t2 = nextTerm; // Update t2 to the newly calculated nextTerm
    }
    cout << endl;

    return 0;
}