FIND PRIME NUMBER IN C++

What is a PRIME NUMBER?

" A Natural number greater than 1 which has only two divisor 1 and itself is called prime number ".

For Example:  

5 is prime, because it has only two divisors 1 and itself.

1. #include<iostream.h>
2. #include<conio.h>
3.         void main()
4.         {
5.          //clrscr();
6.          int number,count=0;
7. cout<<"ENTER NUMBER TO CHECK IT IS PRIME OR NOT ";
8.           cin>>number;
9.            for(int a=1;a<=number;a++)
10.                {
11.                 if(number%a==0)
12.                    {
13.                   count++;
14.                    }
15.                }
16.        if(count==2)
17.          {
18.           cout<<" PRIME NUMBER \n";
19.          }
20.        else
21.          {
22.           cout<<" NOT A PRIME NUMBER \n";
23.          }
24.        //getch();
25.        }