- To print prime numbers between 1 & N
User Input: 12
Output: 2,3,5,7,11
import java.util.Scanner;
public class PrimeNummber {
public static boolean prime(int n) {
if(n<2)return false;
for(int i=2; i<=n/2; i++) {
if(n%i==0) return false;
}
return true;
}
public static void main(String []args) {
int num;
Scanner userInput = new Scanner(System.in);
System.out.print("Enter any +ve number : ");
num = userInput.nextInt();
System.out.println("Your prime numbers between 1 & "+num+" are :");
for(int i=2; i<num; i++)
if(prime(i))System.out.print(i+" ");
}
}
Enter any +ve number : 20 Your prime numbers between 1 & 20 are : 2 3 5 7 11 13 17 19Program
You should know first :
Prime numbers: Numbers greater than 1 & have only 2 factors ( 1 and itself )
Main Logic to check prime :
public static boolean prime(int n){
if(n<2)return false;
for(int i=2;i<=n/2;i++) {
if(n%i==0) return false;
}
return true;
}
We are running the loop n/2
Since, any number can have only factors under its half, except itself
To print all primes :
for(int i=2; i<num; i++) {
//check every number for prime [ if(prime(i)) ], if prime then print the number
}
Concept
Coming Soon !
QuickStrength does not come from winning. Your struggles develop your strengths.