Java program to display prime numbers from 1 to 100

Let’s learn java program to display prime numbers from 1 to 100.

Java program to display prime numbers from 1 to 100

Prime number program in java is most common java interview question. A prime number is one which is divisible by 1 and itself.

java program to display prime numbers from 1 to 100

Here’s the program to display prime numbers from 1 to 100.

public class PrimeNumbersFrom1To100
{
   public static void main(String[] args)
   {
      int maxNumber = 100;
      boolean prime = true;
      String primeNumbers = "";
      for(int a = 1; a <= maxNumber; a++)
      {
         prime = checkPrime(a);
         if(prime)
         {
            primeNumbers = primeNumbers + a + " ";
         }
      }
      System.out.println("Display prime numbers from 1 to " + maxNumber + ": ");
      System.out.println(primeNumbers);
   }
   public static boolean checkPrime(int number)
   {
      int remainder;
      for(int a = 2; a <= number / 2; a++)
      {
         remainder = number % a;
         // if remainder is equal to 0 then number is not prime
         if(remainder == 0)
         {
            return false;
         }
      }
      return true;
   }
}


Output:

Display prime numbers from 1 to 100:
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97


Java program to display prime numbers from 1 to n

Similarly we can display prime numbers from 1 to n.

import java.util.Scanner;
public class PrimeNumber
{
   public static void main(String[] args)
   {
      Scanner sc = new Scanner(System.in);
      int a = 0;
      int number = 0;
      String strPrimeNumber = "";
      System.out.println("Please enter the value of n : ");
      int n = sc.nextInt();
      for(a = 1; a <= n; a++)
      {
         int count = 0;
         for(number = a; number >= 1; number--)
         {
            if(a % number == 0)
            {
               count = count + 1;
            }
         }
         if(count == 2)
         {
            strPrimeNumber = strPrimeNumber + a + " ";
         }
      }
      System.out.println("Java program to display prime numbers from 1 to n : ");
      System.out.println(strPrimeNumber);
      sc.close();
   }
}


Output:

Please enter the value of n : 200
Java program to display prime numbers from 1 to n :
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103 107 109 113 127 131 137 139 149 151 157 163 167 173 179 181 191 193 197 199


Also read – variables in java