first 10 prime numbers code example

Example 1: first prime numbers

#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(){
	//first n prime numbers
	int n;
	cin>>n;
	int i=1;
	while(n--){
		while(!Is_Prime(++i));
		cout<<i<<" ";
	}
}

Example 2: prime numbers from 1 to 100

// find all numbers prime java
public class IsNumberIsSimple {
       
        public static void main (String args[]) {
        
            for ( int i=0; i < 100; i++) {
              isNumberIsSimple(i);
            }     
        }   
        
        public void isNumberIsSimple(num){
        	for ( int i=2; i < num; i++) {
                  if ( num%i == 0) {
                          return;
                  }      
          	}
          	System.out.println("Very well! It's simple! " + num);   
        }
}

//1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97

Example 3: 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<<" ";
	}
}