C++ Exercises: Print the first 20 numbers of the Pell series

Last update on April 12 2025 12:59:49 (UTC/GMT +8 hours)

39. Display First 20 Pell Numbers

Write a C++ program to print the first 20 numbers of the Pell series.

Sample Solution:

C++ Code :

#include <iostream> // Including the input-output stream library

using namespace std; // Using the standard namespace

int main() // Main function
{
    int n, a = 1, b = 0, c; // Declare integer variables: n for iteration, a and b for Pell series calculation, c for storing the current value

    cout << "\n\n Find the first 20 numbers of the Pell series: \n"; // Display purpose
    cout << " --------------------------------------------------\n"; // Display purpose	
    cout << " The first 20 numbers of Pell series are: "<<endl; // Display purpose

    c = 0; // Initializing the first value of Pell series
    cout << " " << c << " "; // Displaying the first value of Pell series

    for (n = 1; n < 20; n++) // Loop to generate the Pell series
    {
        c = a + 2 * b; // Calculate the Pell series value
        cout << c << " "; // Display the current Pell series value
        a = b; // Update 'a' with the previous value of 'b'
        b = c; // Update 'b' with the current value of Pell series
    }
    cout << endl; // Output newline for better readability
}

Sample Output:

Find the first 20 numbers of the Pell series:                         
 --------------------------------------------------                    
 The first 20 numbers of Pell series are:                              
 0 1 2 5 12 29 70 169 408 985 2378 5741 13860 33461 80782 195025 470832
 1136689 2744210 6625109

Flowchart:

For more Practice: Solve these Related Problems:

Write a C++ program to generate the first 20 Pell numbers using an iterative approach with dynamic programming.
Write a C++ program to display Pell numbers by recursively computing each term with memoization.
Write a C++ program to print Pell numbers with formatted output using STL containers for storage.
Write a C++ program to compute and display the first 20 Pell numbers with careful handling of large integer values.

C++ Code Editor:

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