content: package org.example;
  
  import java.util.Scanner;
  
  public class App {
  
      /**
       * TODO: Uses if-else to check if 'number' is positive, negative, or zero.
       * Return:
       *  - "Positive" if number > 0
       *  - "Negative" if number < 0
       *  - "Zero" if number == 0
       */
      public String checkSign(int number) {
          // TODO
          return "";
      }
  
      /**
       * TODO: Uses switch-case to return the day of the week:
       *    1 -> "Monday"
       *    2 -> "Tuesday"
       *    3 -> "Wednesday"
       *    4 -> "Thursday"
       *    5 -> "Friday"
       *    6 -> "Saturday"
       *    7 -> "Sunday"
       * Otherwise, return "Invalid day".
       */
      public String getDayName(int day) {
          // TODO
          return "";
      }
  
      /**
       * TODO: Uses a for loop to calculate factorial of n.
       * Factorial n! = 1 * 2 * 3 * ... * n
       * Assume n >= 0 (factorial(0) = 1)
       */
      public long calculateFactorial(int n) {
          // TODO
          return 0;
      }
  
      /**
       * TODO: Uses a while loop (or for loop) to check if 'number' is prime.
       * Return true if prime, false otherwise.
       * A prime number is a number > 1 that has no divisors other than 1 and itself.
       */
      public boolean isPrime(int number) {
          // TODO
          return false;
      }
  
      /**
       * TODO: Uses a do-while loop to sum integers from 1 up to 'limit'.
       * Example: sumUntil(5) => 1 + 2 + 3 + 4 + 5 = 15
       */
      public int sumUntil(int limit) {
          // TODO
          return 0;
      }
  
      public static void main(String[] args) {
          App app = new App();
  
          // if-else
          System.out.println("checkSign(-10) = " + app.checkSign(-10));  // "Negative", e.g.
          System.out.println("checkSign(0) = " + app.checkSign(0));      // "Zero"
          System.out.println("checkSign(5) = " + app.checkSign(5));      // "Positive"
  
          // switch-case
          System.out.println("\ngetDayName(1) = " + app.getDayName(1));  // "Monday"
          System.out.println("getDayName(7) = " + app.getDayName(7));    // "Sunday"
          System.out.println("getDayName(9) = " + app.getDayName(9));    // "Invalid day"
  
          // for loop
          System.out.println("\ncalculateFactorial(5) = " + app.calculateFactorial(5)); // 120
          System.out.println("calculateFactorial(0) = " + app.calculateFactorial(0));   // 1
  
          // while loop
          System.out.println("\nisPrime(7) = " + app.isPrime(7));   // true
          System.out.println("isPrime(8) = " + app.isPrime(8));     // false
          System.out.println("isPrime(1) = " + app.isPrime(1));     // false
  
          // do-while
          System.out.println("\nsumUntil(5) = " + app.sumUntil(5)); // 15
      }
  }
  
  