w3resource

C Exercises: Explain whether a number is Keith or not

C Numbers: Exercise-37 with Solution

Write a program in C to check if a number is Keith or not (with explanation).

Test Data
Input a number : 1537

Sample Solution:

C Code:

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <math.h>

// Function to count the number of digits in a number
int lenCount(int nm) {
    int ctr = 0;
    while (nm > 0) {
        nm = nm / 10;
        ctr++;
    }
    return ctr;
}

// Main function
int main() {
    // Declare variables
    int num1 = 0, arr1[10], num2 = 0, flg = 0, i = 0, sum = 0, kk;

    // Display information about Keith numbers
    printf("\n\n Check whether a number is Keith or not: \n");
    printf(" Sample Keith numbers: 197, 742, 1104, 1537, 2208, 2580, 3684, 4788, 7385..\n");
    printf(" -----------------------------------------------------------------------\n");
    printf(" Input a number : ");

    // Read input number
    scanf("%d", &num1);
    num2 = num1;

    // Store individual digits of the input number in an array
    for (i = lenCount(num2) - 1; i >= 0; i--) {
        arr1[i] = num1 % 10;
        num1 /= 10;
    }

    // Loop to check if the number is a Keith number or not
    while (flg == 0) {
        // Calculate the sum of the array elements
        for (i = 0; i < lenCount(num2); i++)
            sum += arr1[i];

        // Check conditions for Keith number
        if (sum == num2) {
            flg = 1;
            kk = 1; // Set flag for Keith number
        }
        if (sum > num2) {
            flg = 1;
            kk = 0; // Set flag for non-Keith number
        }

        // Display the current sequence of digits being checked
        for (i = 0; i < lenCount(num2); i++) {
            printf(" %d", arr1[i]);
            if (i != lenCount(num2) - 1) {
                arr1[i] = arr1[i + 1];
                printf(" + ");
            } else {
                arr1[i] = sum;
                printf(" = %d", arr1[i]);
            }
        }
        printf("\n");
        sum = 0;
    }

    // Display the result whether the number is a Keith number or not
    if (kk == 1) {
        printf(" The given number is a Keith Number.\n");
    }
    if (kk == 0) {
        printf(" The given number is not a Keith Number.\n");
    }

    // Return 0 to indicate successful execution of the program
    return 0;
}

Sample Output:

 Input a number : 1537                                                                                        
 1 +  5 +  3 +  7 = 16                                                                                        
 5 +  3 +  7 +  16 = 31                                                                                       
 3 +  7 +  16 +  31 = 57                                                                                      
 7 +  16 +  31 +  57 = 111                                                                                    
 16 +  31 +  57 +  111 = 215                                                                                  
 31 +  57 +  111 +  215 = 414                                                                                 
 57 +  111 +  215 +  414 = 797                                                                                
 111 +  215 +  414 +  797 = 1537                                                                              
 The given number is a Keith Number.

Visual Presentation:

C programming: Explain whether a number is Keith or not.

Flowchart:

Flowchart: Explain whether a number is Keith or not

C Programming Code Editor:

Contribute your code and comments through Disqus.

Previous: Write a program in C to check if a number is Keith or not.
Next: Write a C programming to check whether a given number with base b (2 <= b<= 10) is a Niven number or not.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Become a Patron!

Follow us on Facebook and Twitter for latest update.

It will be nice if you may share this link in any developer community or anywhere else, from where other developers may find this content. Thanks.

https://w3resource.com/c-programming-exercises/numbers/c-numbers-exercise-37.php