C++

Prime Number

A prime number is a natural number greater than 1 that has no positive divisor other than 1 and itself.

Print prime number upto a user given number. 

PROGRAM                                              OUTPUT

#include <iostream>
using namespace std;

int main (){
  int num,i,n;
  bool prime; 
  cout<<"Prime no. upto:";
  cin>>num;
  for(i=3;i<=num;i++){
    prime = true;
    for(n=2;n<=i-1;n++){
      if(i%n == 0){
       prime = false;
       }
    }
    if(prime){
    cout<<i<<" is prime "<<endl;
    } 
   }
return 0;
}
Prime no. upto: 25

3

5

7

11

13

17

19

23