C Exercises: Find Strong Numbers within a range of numbers

C For Loop: Exercise-48 with Solution

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

In a C program to find Strong Numbers within a range:

• Iterate through the range of numbers.
• For each number, calculate the sum of factorials of its digits.
• Compare the sum with the original number; if they match, the number is a Strong Number within the given range.

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h> // Include the standard input/output header file.

void main()  
{  
    int i, n, n1, s1 = 0, j, k, en, sn; // Declare variables to store input and results.
    long fact; // Declare a variable to store factorial.

    printf("\n\nFind Strong Numbers within a range of numbers:\n "); // Print a message.
    printf("------------------------------------------------------\n"); // Print a separator.

    // Prompt the user for the starting and ending range of numbers.
    printf("Input starting range of number : ");  
    scanf("%d", &sn); // Read the starting range.
    printf("Input ending range of number: ");  
    scanf("%d", &en); // Read the ending range.
    printf("\n\nThe Strong numbers are :\n"); // Print a message.

    // Loop to process each number in the given range.
    for (k = sn; k <= en; k++)
    {
        n1 = k; // Store the original number for comparison.
        s1 = 0; // Reset the factorial sum.

        // Loop to process each digit of the number.
        for (j = k; j > 0; j = j / 10) 
        {  
            fact = 1; // Initialize factorial.

            // Loop to calculate factorial of a digit.
            for (i = 1; i <= j % 10; i++)  
            {  
                fact = fact * i;  
            }  
            s1 = s1 + fact;  // Accumulate factorial sum.
        }  

        if (s1 == n1)  
        {  
            printf("%d  ", n1); // Print the strong number.
        }  
    }  

    printf("\n\n"); // Print two new lines.
}
  

Output:

  Find Strong Numbers within an range of numbers:                                                             
 ------------------------------------------------------                                                       
Input starting range of number : 1                                                                            
Input ending range of number: 200                                                                             
                                                                                                              
                                                                                                              
The Strong numbers are :                                                                                      
1  2  145 

Flowchart:

C Programming Code Editor:

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