How to write code for Prime Numbers in Java 2023

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To write a Java program that prints out all the prime numbers between two integers, you can use the following steps: Code for Prime Numbers in Java

  1. Import the java.util.Scanner class, which will allow you to read input from the user.
  2. Create an Scanner object to read input from the user.
  3. Prompt the user to enter two integers: a lower bound and an upper bound. Read these values using the nextInt method of the Scanner object.
  4. Create a loop that iterates over the range of integers between the lower and upper bounds (inclusive). For each integer in the loop, check if it is prime using the following steps:
  5. Create a loop that iterates from 2 to the square root of the integer being checked, inclusive.
  6. Within the inner loop, use the modulo operator (%) to check if the integer being checked is divisible by the current loop variable. If it is, then the integer is not prime, so you can break out of the inner loop and continue with the outer loop.
  7. If the inner loop completes without finding a divisor, then the integer is prime, so you can print it out.

Here is some example code that demonstrates these steps:

import java.util.Scanner;

public class PrimeNumbers {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter lower bound: ");
        int lowerBound = scanner.nextInt();
        System.out.print("Enter upper bound: ");
        int upperBound = scanner.nextInt();
        for (int i = lowerBound; i <= upperBound; i++) {
            boolean isPrime = true;
            for (int j = 2; j <= Math.sqrt(i); j++) {
                if (i % j == 0) {
                    isPrime = false;
                    break;
                }
            }
            if (isPrime) {
                System.out.println(i);
            }
        }
    }
}

This code will prompt the user to enter two integers, and then it will print out all the prime numbers between those two integers (inclusive).

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