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>


int lenCount(int nm)
{  int ctr=0;
    while(nm>0)
    {
        nm=nm/10;
        ctr++;
     }
     return ctr; 
}
int main()
{
    int num1=0,arr1[10],num2=0,flg=0,i=0,sum=0,kk;
	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 : ");
    scanf("%d",&num1);
    num2=num1;
    for(i=lenCount(num2)-1;i>=0;i--)
    {
        arr1[i]=num1 % 10;
        num1/=10;
    }
    while(flg==0)
    {
        for(i=0;i<lenCount(num2);i++)
            sum+=arr1[i];
        if(sum==num2)
        {
            flg=1;
            kk=1;
        }
        if(sum>num2)
        {
            flg=1;
            kk=0;
        }
        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;
    }
            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");
            }            
}

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.

Pictorial Presentation:

Flowchart:

C Programming Code Editor:

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