C++ Exercises: Check if a number is Keith or not

C++ Numbers: Exercise-41 with Solution

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

Sample Output:
Input a number : 197
1 + 9 + 7 = 17
9 + 7 + 17 = 33
7 + 17 + 33 = 57
17 + 33 + 57 = 107
33 + 57 + 107 = 197
The given number is a Keith Number.

Sample Solution:

C++ Code:

#include<bits/stdc++.h>
using namespace std;

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;
	cout << "\n\n Check whether a number is Keith or not: \n";
	cout <<" Sample Keith numbers: 197, 742, 1104, 1537, 2208, 2580, 3684, 4788, 7385..\n";
	cout << " -----------------------------------------------------------------------\n";	
	cout<<" Input a number : ";
    cin>>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++)
        {
            cout<<" "<<arr1[i];
            if(i!=lenCount(num2)-1)
                {arr1[i]=arr1[i+1];
                cout<<" + ";}
            else
                {arr1[i]=sum;
                cout<<" = "<<arr1[i];}
        }
        cout<<endl;
        sum=0;
    }
            if(kk==1)
            {
            cout<<" The given number is a Keith Number.\n";
            }
            if(kk==0)
            {
            cout<<" The given number is not a Keith Number.\n";
            }            
}

Sample Output:

 Check whether a number is Keith or not:                               
 Sample Keith numbers: 197, 742, 1104, 1537, 2208, 2580, 3684, 4788, 7385..                                                                   
 -----------------------------------------------------------------------                                                                      
 Input a number : 197                                                  
 1 +  9 +  7 = 17                                                      
 9 +  7 +  17 = 33                                                     
 7 +  17 +  33 = 57                                                    
 17 +  33 +  57 = 107                                                  
 33 +  57 +  107 = 197                                                 
 The given number is a Keith Number.

Flowchart:

C++ Code Editor:

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