Prime numbers

#include<iostream>
using namespace std;
int isPrime(int N)
{
    if(N == 1) return 0;
    if( N == 2) return 1;
    for(int i = 2; i*i <= N; ++i)
    {
        if(N%i == 0)
            return 0;
    }
    return 1;
}
void displayPrime(int l, int r)
{
    for(int i = l; i <= r; ++i)
    {
        if(isPrime(i))
            cout << i << " ";
    }
}
 int main()
 {
     printf("Prime Numbers\n");
     printf("Please choose what you want\n");
     printf("1. Checking if a number is Prime\n");
     printf("2. Printing all prime numbers of given range\n");
     int x, N, l, r;
     cin >> x;
     if(x == 1){
        cout << "Enter a number: ";
        cin >> N;
        if(isPrime(N)) cout << "The number is Prime" << endl;
        else cout << "The number is non-Prime" << endl;
     }
     else if(x == 2) {
        cout << "Enter starting number: ";
        cin >> l;
        cout << "Enter ending number: ";
        cin >> r;
        displayPrime(l, r);
     }
     else cout << "Invalid. Please choose option 1 or 2." << endl;
 }