print prime numbers in java

1// Java program to print prime numbers in a given range
2public class PrimeNumberRangeDemo 
3{
4   public static void main(String[] args) 
5   {
6      int lowerRange = 10, higherRange = 50;  
7      while(lowerRange < higherRange) 
8      {
9         boolean flag = false;
10         for(int a = 2; a <= lowerRange / 2; ++a) 
11         {
12            if(lowerRange % a == 0)
13            {
14               flag = true;
15               break;
16            }
17         }
18         if(!flag && lowerRange != 0 && lowerRange != 1)
19             System.out.print(lowerRange + " ");
20         ++lowerRange;
21      }
22   }
23}

1public class Prime {
2    public static void main(String[] args) {
3
4        int num = 29;
5        boolean flag = false;
6        for(int i = 2; i <= num/2; ++i){
7            if(num % i == 0){
8                flag = true;
9                break;
10            }
11        }
12
13        if (!flag)
14            System.out.println(num + " is a prime number.");
15        else
16            System.out.println(num + " is not a prime number.");
17}}

1// Java program to print prime numbers upto n
2import java.util.Scanner;
3public class PrimeNumberUptoN
4{
5   public static void main(String[] args)
6   {
7      Scanner sc = new Scanner(System.in);
8      int a = 0;
9      int n = 0;
10      String strPrime = "";
11      System.out.println("Please enter the value of n: ");
12      int number = sc.nextInt();
13      for(a = 1; a <= number; a++)
14      {
15         int counter = 0;
16         for(n = a; n >= 1; n--)
17         {
18            if(a % n == 0)
19            {
20               counter = counter + 1;
21            }
22         }
23         if(counter == 2)
24         {
25            strPrime = strPrime + a + " ";
26         }
27      }
28      System.out.println("prime numbers upto n are: ");
29      System.out.println(strPrime);
30      sc.close();
31   }
32}

1public class Prime {
2    public static void main(String[] args) {
3
4        int num = 29;
5        boolean flag = false;
6        for(int i = 2; i <= num/2; ++i){
7            if(num % i == 0){
8                flag = true;
9                break;
10            }
11        }
12
13        if (!flag)
14            System.out.println(num + " is a prime number.");
15        else
16            System.out.println(num + " is not a prime number.");
17}}
18Source:www.progra
19

1import java.util.Scanner;
2 
3public class PrimeNumberChecker {
4    public static void main(String[] args) {
5        System.out.println("Enter a number to check Prime or Not");
6        Scanner scanner = new Scanner(System.in);
7        int number = scanner.nextInt();
8        int i = 2, count = 0;
9        while (i <= number / 2) {
10            if (number % i == 0) {
11                count++;
12                break;
13            }
14            i++;
15        }
16        if (count == 0) {
17            System.out.println(number + " is prime number");
18        } else {
19            System.out.println(number + " is not a prime number");
20        }
21    }
22}

1import java.util.ArrayList;
2import java.util.List;
3import java.util.Scanner;
4 
5public class PrimeNumberChecker3 {
6 
7    public static List<Integer> generatePrimeInRange(int startRange, int endRange) {
8        if (startRange >= endRange) {
9            System.out.println("endRange must be greater then startRange");
10            System.exit(0);
11        }
12        List<Integer> primeList = new ArrayList<>();
13        while (startRange <= endRange) {
14            int i = 2, count = 0;
15            while (i <= startRange / 2) {
16                if (startRange % i == 0) {
17                    count++;
18                    break;
19                }
20                i++;
21 
22            }
23            if (count == 0) {
24                primeList.add(startRange);
25            }
26            startRange++;
27        }
28        return primeList;
29    }
30 
31    public static void main(String[] args) {
32        System.out.println("Enter a number range to generate prime numbers in between");
33        Scanner scanner = new Scanner(System.in);
34        int number1 = scanner.nextInt();
35        int number2 = scanner.nextInt();
36        List<Integer> primeNumbers = generatePrimeInRange(number1, number2);
37        System.out.println("Prime Numbers are");
38        System.out.println(primeNumbers);
39 
40    }
41}