how to find the prime number using c++(with simple coding)

how to find prime number in c++:
This is the source code for determining that given number is prime or not
#include<iostream.h>
#include<conio.h>
main()
{
      int x;
      for(int i=1;i<=100;i++){
      cout<<"enter the number"<<endl;
      cin>>x;
      if(x==2 || x==3 || x==5){
             cout<<"number is prime"<<endl;
             }
      else if(x%2==0 || x%3==0 || x%5==0)
      {
                cout<<"not prime"<<endl;
                }
                else
                {
                    cout<<"number is prime"<<endl;
                    }
                     
                       }
                    getch();
                    }
End