all natural prime numbers less than 20 code example
Example: 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<<" ";
}
}