check if prime c++ code example
Example 1: c++ find prime numbers
#include <iostream>
using namespace std;
int main()
{
int n, i;
bool isPrime = true;
cout << "Enter a positive integer: ";
cin >> n;
for(i = 2; i <= n / 2; ++i)
{
if(n % i == 0)
{
isPrime = false;
break;
}
}
if (isPrime)
cout << "This is a prime number";
else
cout << "This is not a prime number";
return 0;
}
Example 2: program to know if a number is prime
#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(){
long long x;
cin>>x;
if(Is_Prime(x))cout<<"Is Prime";
else cout<<"Is not Prime";
}