java to print all prime numbers smaller than n code example
Example 1: Java program to print prime numbers from 2 to n
import java.util.Scanner;
public class PrimeNumberFrom2Ton
{
public static void main(String[] args)
{
int loop, max;
System.out.print("Please enter highest (maximum) number: ");
Scanner sc = new Scanner(System.in);
max = sc.nextInt();
for(loop = 2; loop < max; ++loop)
{
if(findPrime(loop))
{
System.out.println(loop);
}
}
sc.close();
}
public static boolean findPrime(int number)
{
int a;
boolean boolPrime = true;
for(a = 2; a < number / 2; a++)
{
if(number%a == 0)
{
boolPrime = false;
break;
}
}
return boolPrime;
}
}
Example 2: Java program to print prime numbers upto n
import java.util.Scanner;
public class PrimeNumberUptoN
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
int a = 0;
int n = 0;
String strPrime = "";
System.out.println("Please enter the value of n: ");
int number = sc.nextInt();
for(a = 1; a <= number; a++)
{
int counter = 0;
for(n = a; n >= 1; n--)
{
if(a % n == 0)
{
counter = counter + 1;
}
}
if(counter == 2)
{
strPrime = strPrime + a + " ";
}
}
System.out.println("prime numbers upto n are: ");
System.out.println(strPrime);
sc.close();
}
}