Lesson 1: Introduction to Java

Activity 1: Printing the Results of Simple Arithmetic Operations

Solution:

1. Create a class named Operations as follows:

   public class Operations
   {

2. Within main(), print a sentence describing the operation on the values you will be performing along with the result:

       public static void main(String[] args) {
           System.out.println("The sum of 3 + 4 is " + (3 + 4));
           System.out.println("The product of 3 + 4 is " + (3 * 4));
       }
   }

   The output will be as follows:

   The sum of 3 + 4 is 7
   The product of 3 + 4 is 12

Activity 2: Reading Values from the User and Performing Operations Using the Scanner Class.

Solution:

1. Right-click the src folder and select New | Class.

2. Enter ReadScanner as the class name, and then click OK.

3. Import the java.util.Scanner package:

   import java.util.Scanner;

4. In the main() enter the following:

   public class ReadScanner
   {
       static Scanner sc = new Scanner(System.in);
     public static void main(String[] args) {
       System.out.print("Enter a number: ");
       int a = sc.nextInt();
       System.out.print("Enter 2nd number: ");
       int b = sc.nextInt();
       System.out.println("The sum is " + (a + b) + ".");
   
       }
   }

5. Run the main program.

   The output will be as follows:

   Enter a number: 12                                                                                                             
   Enter 2nd number: 23
   The sum is 35.

Activity 3: Calculating the Percent Increase or Decrease of Financial Instruments

Solution:

1. Right-click the src folder and select New | Class.

2. Enter StockChangeCalculator as the class name, and then click OK.

3. Import the java.util.Scanner package:

   import java.util.Scanner;

4. In the main() enter the following:

   public class StockChangeCalculator{
   static Scanner sc = new Scanner(System.in);
   public static void main(String[] args) {
       System.out.print("Enter the stock symbol: ");
       String symbol = sc.nextLine();
       System.out.printf("Enter %s's day 1 value: ", symbol);
       double day1 = sc.nextDouble();
       System.out.printf("Enter %s's day 2 value: ", symbol);
       double day2 = sc.nextDouble();
       double percentChange = 100 * (day2 - day1) / day1;
       System.out.printf("%s has changed %.2f%% in one day.", symbol, percentChange);
   }
   }

5. Run the main program.

   The output should be similar to:

   Enter the stock symbol: AAPL                                                                                                             
   Enter AAPL's day 1 value: 100                                                                                                           
   Enter AAPL's day 2 value: 91.5                                                                                                           
   AAPL has changed -8.50% in one day.