number of primes less than or equal to n code example

Example 1: Write a program that prints all prime numbers less than 1,000,000

public class Main {
  public static void main(String[] args) {
    for (int i = 2; i < 1_000_000; ++i) {
      boolean isPrime = true;
      int sqrt = (int)Math.ceil(Math.sqrt(i));
      for (int divisor = 2; divisor <= sqrt; ++divisor) {
        if (i % divisor == 0) {
          isPrime = false;
          break;
        }
      }
      if (isPrime) {
        System.out.println(i);
      }
    }
  }
}

Example 2: first prime numbers less than

#include<bits/stdc++.h>
using namespace std;
bool Is_Prime(long long x){
	if(x%2==0)return false;
	for(int i=3;i*i<=x;i+=2)
		if(x%i==0)return false;
	return true;
}
int main(){
	//primes less than n
	int n;
	cin>>n;
	int primes=0,i=1;
	while(primes++<n){
		while(!Is_Prime(++i));
		cout<<i<<" ";
	}
}