C++ Exercises: Find Strong Numbers within a range of numbers

Last update on April 12 2025 13:00:10 (UTC/GMT +8 hours)

40. Find Strong Numbers Within a Range

Write a C++ program to find Strong Numbers within a range of numbers.

Sample Solution:

C++ Code:

#include <iostream>
using namespace std;

int main()
{
    int i, n, n1, s1 = 0, j, k, en, sn; // Declare variables for iteration and range of numbers
    long fact; // Declare a variable to store factorial

    // Prompt the user to input the range of numbers to find Strong numbers
    cout << "\n\n Find Strong Numbers within a range of numbers:\n";
    cout << "----------------------------------------------------\n";
    cout << " Input the starting range of numbers: ";
    cin >> sn; // Input starting range
    cout << " Input the ending range of numbers: ";
    cin >> en; // Input ending range
    cout << " The Strong numbers within the range are: ";

    // Loop through the numbers within the specified range
    for (k = sn; k <= en; k++) 
    {
        n1 = k; // Store the current number in n1
        s1 = 0; // Initialize sum of factorials as 0

        // Loop to calculate the sum of factorials of digits for each number
        for (j = k; j > 0; j = j / 10) 
        {
            fact = 1; // Initialize factorial as 1 for each digit

            // Calculate factorial for each digit
            for (i = 1; i <= j % 10; i++) 
            {
                fact = fact * i; // Multiply each digit's factorial
            }

            s1 = s1 + fact; // Accumulate the sum of factorials for each digit
        }

        // Check if the sum of factorials of digits is equal to the original number
        if (s1 == n1)
            cout << n1 << "  "; // Print the Strong number if found within the range
    }
    cout << endl;
}

Sample Output:

Check whether a number is Strong Number or not:                                                
 -------------------------------------------------------                                             
 Input starting range of number: 1  
 Input ending range of number: 500  
 The Strong numbers are: 1  2  145

Flowchart:

C++ Code Editor:

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