C++ Program to check whether a number is an Automorphic number or not

Automorphic  Number in C++

In this post, we will learn to code Automorphic Number in C++

An Automorphic number is a special number, whose’s square ends with the same digits as the number itself

C++ Program to check whether a number is an Automorphic number or not

Algorithm:-

  1. Calculate the square of the number
  2. Extract digits of the square from the end
  3. If end digits and the number become equal at some point
  4. Then its an automorphic number
 
Automorphic Number in C++

C++ Code:-

Run
#include <iostream>
using namespace std;

int isAutomorphic(int n){
    
    int square = n * n;
    
    while(n != 0)
    {
        // means not automorphic number
        if(n % 10 != square % 10){
            return 0;
        }
        
        // reduce down numbers
        n /= 10;
        square /= 10;
    }
    // if reaches here means automorphic number
    return 1;
}

int main ()
{
    int n = 376, sq = n * n ;
    
    if(isAutomorphic(n))
        cout << "Num: "<< n << ", Square: " << sq << " - is Automorphic";
    else
        cout << "Num: "<< n << ", Square: " << sq << " - is not Automorphic";
    

}
// Time complexity: O(N)
// Space complexity: O(1)

Output

Num: 376, Square: 141376 - is Automorphic

Prime Course Trailer

Related Banners

Get PrepInsta Prime & get Access to all 150+ courses offered by PrepInsta in One Subscription

One comment on “C++ Program to check whether a number is an Automorphic number or not”


  • Abhay

    // to check number is automorphic or not
    #include
    using namespace std;
    int main()
    {
    int a,i=1;
    cin>>a;
    int sqr=a*a;
    while(i<a)
    {
    i=i*10;
    }
    if(sqr%i==a)
    {cout<<"\nno is automorphic";}
    else
    {cout<<"\nno is not automorphic";}
    return 0;
    }