C++ Exercises: Find Perfect numbers and number of Perfect numbers between 1 to 1000

Last update on December 20 2024 12:24:39 (UTC/GMT +8 hours)

Write a program in C++ to find Perfect numbers and the number of Perfect numbers between 1 and 1000.

Visual Presentation:

Sample Solution:

C++ Code :

# include <iostream> // Include necessary libraries
# include <string>

using namespace std;

int main()
{
    int i = 1, u = 1, sum = 0, ctr = 0; // Initialize variables i, u, sum, and ctr
    cout << "\n\n Find the Perfect numbers and number of Perfect numbers between 1 to 1000:\n"; // Display message for user
    cout << "------------------------------------------------------------------------------\n";

    cout << "The Perfect numbers are : \n"; // Display message for user

    while (i <= 1000) // Loop through numbers from 1 to 1000
    {
        while (u <= 1000) // Nested loop to find divisors of i
        {
            if (u < i) // Check if u is less than i
            {
                if (i % u == 0) // Check if u is a divisor of i
                    sum = sum + u; // Add u to the sum if it's a divisor of i
            }
            u++; // Increment u by 1 in each iteration
        }

        if (sum == i) // Check if the sum of divisors is equal to i
        {
            ctr++; // Increment the counter if the number is perfect
            cout << i << " is a Perfect number." << "\n"; // Display if i is a Perfect number
        }

        i++; // Move to the next number
        u = 1; // Reset u to 1 for the next iteration
        sum = 0; // Reset sum for the next iteration
    }

    cout << "Number of Perfect numbers between 1 to 1000 is: " << ctr << "\n"; // Display the count of Perfect numbers
}

Sample Output:

 Find the Perfect numbers and number of Perfect numbers between 1 to 1000:                                                                    
------------------------------------------------------------------------------                                                                
The Perfect numbers are :                                              
6 is a perfect number.                                                 
28 is a perfect number.                                                
496 is a perfect number.                                               
Number of perfect numbers between 1 to 1000 is: 3 

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