Generate the First N Terms of the Fibonacci Series

Given an integer N >= 1, print the first N numbers of the Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8, 13... using a three-variable sliding window.

Step 1: Start.
Step 2: Read positive integer N.
Step 3: If N <= 0:
         Print 'Invalid count' and Stop.
Step 4: If N == 1:
         Print '0' and Stop.
Step 5: Initialize T1 = 0, T2 = 1.
Step 6: Print T1, T2.
Step 7: Initialize count = 3.
Step 8: While (count <= N):
         nextTerm = T1 + T2
         Print nextTerm
         T1 = T2
         T2 = nextTerm
         count = count + 1
Step 9: Stop.

         +-----------------+
         |     [ START ]   |
         +-----------------+
                  |
                  v
         +-----------------+
         |     Read N      |
         +-----------------+
                  |
                  v
               /     \
             / N <= 0? \ ---YES--> [Print Invalid] --> [STOP]
             \         /
                  | NO
                  v
               /     \
             /  N == 1?\ ---YES--> [Print 0] --------> [STOP]
             \         /
                  | NO
                  v
         +-----------------+
         | T1 = 0, T2 = 1  |
         | Print T1, T2    |
         | count = 3       |
         +-----------------+
                  |
                  v
               /     \
             /count<=N?\ ---NO---> [STOP]
             \         /
                  | YES
                  v
         +-----------------+
         | next = T1 + T2  |
         | Print next      |
         | T1=T2, T2=next  |
         | count=count+1   |
         +-----------------+
                  |
                  +------> (Loop to count <= N?)

Edit the code directly with the Edit Code button, provide custom inputs, and press Run Code to compile and execute in the live terminal console below!

#include <iostream>
using namespace std;

int main() {
    int n;
    cout << "Enter the number of terms N: ";
    if (!(cin >> n) || n <= 0) {
        cout << "Please enter a positive integer (N >= 1).\n";
        return 1;
    }

    long long t1 = 0, t2 = 1;
    cout << "\nFibonacci Series (" << n << " terms):\n";

    if (n == 1) {
        cout << t1 << "\n";
        return 0;
    }

    cout << t1 << ", " << t2;
    for (int count = 3; count <= n; ++count) {
        long long nextTerm = t1 + t2;
        cout << ", " << nextTerm;
        t1 = t2;
        t2 = nextTerm;
    }
    cout << "\n";
    return 0;
}

Input:
8

Output:
Fibonacci Series (8 terms):
0, 1, 1, 2, 3, 5, 8, 13