Prime in C++

[hirunisha]

Hi Im a beginner in C++. I tried to do these but couldnt.
Pls hekp me to do these. thanks.

1. Design and implement a class called PrimeChecker. An instance of this
class will be able to check if a number between 2-10000 is prime. The class
stores the consecutive primes 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37,
41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101 in an array and uses
these to check if the given number is prime.
The class has the following public methods:
(a) Constructor
(b) Destructor
(c) IsPrime() which takes a parameter which is an integer in the range
1-10000 and returns a boolean.

2. Extend the class above so that if the number x (which may now be more
than 10000) to check is greater than the square of the largest prime in
the list of consecutive primes then the class adds new consecutive primes
to its internal array (the largest prime it adds is just greater than the
square-root of x.). Assume that you will never need to hold more
than 1000 consecutive primes.

[AricC]

Use modulus

#include <iostream>
 
using namespace std;
 
int main()
{
    int num;
    cin >> num;
    // num % 2 computes the remainder when num is divided by 2
    if ( num % 2 == 0 )
    {
        cout << num << " is even ";
    }
 
    return 0;
} 
 

[hirunisha]

HI, thanks for the reply.
But this won't sort my problem, its relate to classes.

[hirunisha]

I could write a porg to check whether a number is prime or not.

#include<iostream>
#include <cmath>
using namespace std;

int main()
{
int n;
cout<<" Enter a number to find if its a prime number "<<endl;
cin>>n;

bool a =true;

for(int i=2;i<sqrt(n);i++)
{

if(n%i==0)
{
a=false;
break;
}
}


if(a==false)
cout<<n<<" is not a prime number"<<endl;
else
cout<<n<<" is a prime number"<<endl;

}


I dnt knw hw to develope this for the followings:


1. Design and implement a class called PrimeChecker. An instance of this
class will be able to check if a number between 2-10000 is prime. The class
stores the consecutive primes 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37,
41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101 in an array and uses
these to check if the given number is prime.
The class has the following public methods:
(a) Constructor
(b) Destructor
(c) IsPrime() which takes a parameter which is an integer in the range
1-10000 and returns a boolean.

2. Extend the class above so that if the number x (which may now be more
than 10000) to check is greater than the square of the largest prime in
the list of consecutive primes then the class adds new consecutive primes
to its internal array (the largest prime it adds is just greater than the
square-root of x.). Assume that you will never need to hold more
than 1000 consecutive primes.