Strong Number In C

Source Code
Strong Number


C Program To Check Strong Number or Not

Strong number is a special number whose sum of the factorial of digits
is equal to the original number.

Example:
Given Number : 145
It is a Strong Nuumber.
Since: 1! + 4! + 5! = 145
1! = 1*1 = 1
4! = 1*2*3*4 = 24
5! = 1*2*3*4*5 = 120
Example:
Given Number : 125
It is Not a Strong Nuumber.
Since:
1! + 2! + 5! = 123
1! = 1*1 = 1
2! = 1*2 = 2
5! = 1*2*3*4*5 = 120

To check if a number is a Strong Number in C
you can use the following algorithm:
  1. Read the input number.
  2. Create a copy of the input number.
  3. Initialize a variable sum to 0.
  4. While the given number is not equal to 0,perform the following steps:
    • Get the last digit of the num by using the modulo operator (%).
    • Calculate the factorial of the last digit and add it to the sum.
    • Divide the num by 10 to remove the last digit.
  5. Check if the sum is equal to the copy number.
    • If they are equal, the number is a Strong Number.
      Otherwise, it is not.
  6. Print the result.
Here is an example implementation in C:

Source Code

// C Program To Check Strong Number or Not
#include<stdio.h>
#include<conio.h>
   void main()
      {
         int num , Rd , i , fact , sum = 0 , ncopy ;
         printf("Enter a Number To Check : ");
         scanf("%d",&num);
         ncopy=num;
         while( num!=0 )
              {
                 Rd   = num % 10 ;
                 fact = 1;
                    for( i=1; i<=Rd; i++ )
                        {
                           fact = fact * i ;
                        }
                 sum = sum + fact ;
                 num = num / 10;
              }
        if ( sum==ncopy )
           printf("It is a Strong Number . ");
        else
           printf("It is Not a Strong Number . ");
        getch();
      }

Output

Sample Input :
Enter a Number To Check : 145
Sample Output:
It is a Strong Number

Sample Input :
Enter a Number To Check : 123
Sample Output:
It is Not a Strong Number

In this algorithm, the input number is processed to calculate the sum of the factorials of its digits. A separate factorial function is used to calculate the factorial of a given number. The algorithm iterates through each digit of the number, calculates its factorial, and adds it to the sum. Finally, it checks if the sum is equal to the copy number to determine if it is a Strong Number.

Please note that this implementation assumes that the input number is a positive integer. You may need to add additional checks for negative numbers or other cases depending on your requirements.

Variable Description
Data Type Variable Name Description
int num To Store an Integer That You Want To Check
int Rd To Store Last Digit of the Number During Loop
int i To Control The For Loop
int fact To Store Factorial of Right Digit
int sum To Store sum of the factorials of digits
int ncopy To Store Copy of Input Number

Looping Related Programs