C++ Program to check whether a number is Prime or not

Program:

#include<iostream>

using namespace std;

int main()

{

int n, a=2;

bool r=false;

cout<<"Enter a number=";

cin>>n;

for(int a=2; a<n; a++)

{

if(n%a==0)

{

r=true;

}

}

if(r)

{

cout<<n<<" is not a prime number.";

}

else

{

if(n!=0&&n!=1)

{

cout<<n<<" is a prime number.";

}

else

{

cout<<"It is not a prime Number.";

}

}

return 0;

}

Output: