w3resource

C++ Exercises: Check if a given number is circular prime or not

C++ Numbers: Exercise-30 with Solution

Write a program in C++ to check if a given number is circular prime or not.

Sample Solution:

C++ Code :

#include<iostream>
#include<cmath>
using namespace std;
int flg;
void chkPrime(long int n)
{
    long int i;
    i=n-1;
    while(i>=2)
    {
        if(n%i==0)
        {
            flg=1;
        }
        i--;
    }
}
void AllCombination(long int a)
{
  long int b1,c1,d1,e1,i,j,k,s1,z1,v1,x[8],y[8],m;
  b1=a;
  i=0;
  while(b1>0)
  {
      y[i]=b1 % 10;
      b1=b1/10;
      i++;
  }
  c1=0;
  for(j=i-1;j>=0;j--)
  {
    x[c1]=y[j];
    c1++;
  }
  m=i;
  while(m>0)
  {
     c1=m-1;
     d1=i-1;
     e1=0;
     s1=0;
     while(e1<i)
     {
       z1=pow(10,d1);
       v1=z1*x[c1%i];
       c1++;
       d1--;
       e1++;
       s1=s1+v1;
     }
     m--;
     chkPrime(s1);
  }
}
int main()
{
    long int num1;
 cout << "\n\n Check whether a given number is circular prime or not: \n";
 cout << " -----------------------------------------------------------\n";
    cout<<" Input a Number: ";
    cin>>num1;
      flg=0;
      AllCombination(num1);
      if(flg==0)
      {
        cout << " The given number is a circular prime Number."<<endl;
      }
    else
    {
        cout << " The given number is not a circular prime Number."<<endl;
    }
    return 0;	
	cout<<endl;
}

Sample Output:

Check whether a given number is circular prime or not:                
 -----------------------------------------------------------           
 Input a Number: 11                                                    
 The given number is a circular prime Number

Flowchart:

Flowchart: Check if a given number is circular prime or not
Flowchart: Check if a given number is circular prime or not
Flowchart: Check if a given number is circular prime or not

C++ Code Editor:

Contribute your code and comments through Disqus.

Previous: Write a program in C++ to count the Amicable pairs in an array.
Next: Write a program in C++ to find circular prime numbers upto a specific limit.

What is the difficulty level of this exercise?



Share this Tutorial / Exercise on : Facebook and Twitter

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