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C++ Exercises: Find Narcissistic decimal numbers within a specific range

C++ Numbers: Exercise-37 with Solution

Write a program in C++ to find Narcissistic decimal numbers within a specific range.

Sample Solution:

C++ Code :

#include <iostream>
#include <cmath>
using namespace std;
int main() 
{
    int nl,nu;
 cout << "\n\n Find the Narcissistic decimal numbers between a specific range: \n";
 cout << " --------------------------------------------------------------------\n";
 	cout << " Input the lower limit: ";
    cin>>nl;	
	cout << " Input a upper limit: ";
    cin>>nu;		
  cout << " The Narcissistic decimal numbers between "<<nl<<" and "<<nu<<" are: \n";
    int i,ctr,j,orn,n,m,sum;
    for(orn=nl;orn<=nu;orn++)
    {
    ctr=0;
    sum=0;
    n=orn;
       while(n>0) 
       {
          n=n/10;
           ctr++;
       }
        n=orn;
       while(n>0) 
       {
          m=n % 10;
          sum=sum+pow(m,ctr);
          n=n/10;
       }
       if(sum==orn)
       {
           cout<<" "<<orn<<" ";
    }
}
	cout<<endl;
}

Sample Output:

Find the Narcissistic decimal numbers between a specific range:       
 --------------------------------------------------------------------  
 Input the lower limit: 25                                             
 Input a upper limit: 200                                              
 The Narcissistic decimal numbers between 25 and 200 are:              
 153 

Flowchart:

Flowchart: Find Narcissistic decimal numbers within a specific range

C++ Code Editor:

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Previous: Write a program in C++ to generate Mersenne primes within a range of numbers.
Next: Write a program in C++ to check whether a given number is palindrome or not.

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C++ Programming: Tips of the Day

How to use the PI constant in C++?

On some (especially older) platforms (see the comments below) you might need to

#define _USE_MATH_DEFINES and then include the necessary header file:
#include<math.h>

and the value of pi can be accessed via:

M_PI

In math.h (2014) it is defined as:

# define M_PI           3.14159265358979323846  /* pi */

but check your math.h for more. An extract from the "old" math.h (in 2009):

/* Define _USE_MATH_DEFINES before including math.h to expose these macro
 * definitions for common math constants.  These are placed under an #ifdef 
 * since these commonly-defined names are not part of the C/C++ standards.
 */

However:

  1. on newer platforms (at least on my 64 bit Ubuntu 14.04) I do not need to define the _USE_MATH_DEFINES
  2. On (recent) Linux platforms there are long double values too provided as a GNU Extension:
# define M_PIl          3.14159265358979323846

Ref: https://bit.ly/3G4BgzQ