Prime number detection using C++

Prime Number: It is a natural number other than $1$ which has only two divisors, $1$ and itself.

Examples:

$3$ is a prime number. It has two divisors $1$ and $3$ itself.
$13$ is a prime number. It has two divisors $1$ and $13$ itself.

Algorithm:

Steps:

1. Take an integer to check whether it is prime or not.
2. Divide the integer by the all the numbers from 1 to till that number
3. Count the number of times the integer is divisible
4. If the count is 2 then it is a prime number
5. Otherwise it is not a prime number.

  

#include "iostream"
#include "conio.h"

using namespace std;

        int main()
        {

         int n, count=0;

        cout<< "Enter a number to check prime : ";
        cin>>n;

        for(int a=1;a<=number; a++)
            {
                if(number%a==0)
                {
                    count++;
                }
            }
        if(count==2)
            {
                cout<<" PRIME NUMBER \n";
            }
        else
            {
                cout<<" NOT A PRIME NUMBER \n";
            }

       return (0);
    }

INPUT:     Enter a number to check prime : $7$

OUTPUT: PRIME NUMBER

INPUT:       Enter a number to check prime : $15$

OUTPUT:  NOT A PRIME NUMBER