Primitives Notebook

• Listing the types of primitives:
• Division with ints and doubles:
• Celsius to Fahrenheit Converter
• Inputting primitive data:

Listing the types of primitives:

public class ListPrimitives {
    public static void main(String[] args) {
      
      // assigning variable values
      int anInt = 505;
      double aDouble = 99.9;
      boolean aBoolean = true;
      char aChar='\u0021';  
      // not a primitive but essential
      String aString = "Look over there!";
  
      System.out.println("Types of Primitives:");
      System.out.println("--> Integer: " + anInt);
      System.out.println("--> Double: " + aDouble);
      System.out.println("--> Character: " + aChar);
      System.out.println("--> Boolean: " + aBoolean);
      System.out.println("--> String: " + aString);
    }
  }
  ListPrimitives.main(null)

Types of Primitives:
--> Integer: 505
--> Double: 99.9
--> Character: !
--> Boolean: true
--> String: Look over there!

Division with ints and doubles:

public class Division {
    public static void main(String[] args) {
  
      // setting the variables
      int divided = 17 / 24;
      double doubleDivided = 17.0 / 24.0;
  
      // printing out the division in int and double form
      System.out.println("Integer division with 17/24 is: " + divided);
      // %.2f limits the # of decimal values displayed
      System.out.println("Double division with 17.0/24.0 is: " + String.format("%.2f", doubleDivided));      
    }
  }
  // makes it so you can print the code's output
  Division.main(null)

Integer division with 17/24 is: 0
Double division with 17.0/24.0 is: 0.71

Celsius to Fahrenheit Converter

public class CtoF {
    public static void main(String[] args) {
  
      System.out.println("Celsius to Fahrenheit Converter:");

      System.out.println("Degrees Celsius: 55 -->");
      int celsius = 55;
      int fahrenheit = ((celsius*9)/5)+32;
      System.out.println("\tDegrees Fahrenheit: " + fahrenheit);

      System.out.println("Degrees Celsius: 78 -->");
      int celsius1 = 78;
      int fahrenheit1 = ((celsius1*9)/5)+32;
      System.out.println("\tDegrees Fahrenheit: " + fahrenheit1);

      System.out.println("Degrees Celsius: 11 -->");
      int celsius2 = 11;
      int fahrenheit2 = ((celsius2*9)/5)+32;
      System.out.println("\tDegrees Fahrenheit: " + fahrenheit2);
    
    }
  }
  // makes it so you can print the code's output
  CtoF.main(null)

Celsius to Fahrenheit Converter:
Degrees Celsius: 55 -->
	Degrees Fahrenheit: 131
Degrees Celsius: 78 -->
	Degrees Fahrenheit: 172
Degrees Celsius: 11 -->
	Degrees Fahrenheit: 51

Inputting primitive data:

// java style to import library
import java.util.Scanner;

// class must alway have 1st letter as uppercase, CamelCase is Java Class convention
public class ScanPrimitives {
    public static void main(String[] args) {    
        Scanner input;

        // primitive int
        input = new Scanner(System.in);
        System.out.print("Enter an integer: ");
        try {
            int sampleInputInt = input.nextInt();
            System.out.println(sampleInputInt);
        } catch (Exception e) {  // if not an integer
            System.out.println("Not an integer (form like 159), " + e);
        }
        input.close();

        // primitive double
        input = new Scanner(System.in);
        System.out.print("Enter a double: ");
        try {
            double sampleInputDouble = input.nextDouble();
            System.out.println(sampleInputDouble);
        } catch (Exception e) {  // if not a number
            System.out.println("Not an double (form like 9.99), " + e);
        }
        input.close();

        // primitive boolean
        input =  new Scanner(System.in);
        System.out.print("Enter a boolean: ");
        try {
            boolean sampleInputBoolean = input.nextBoolean();
            System.out.println(sampleInputBoolean);
        } catch (Exception e) {  // if not true or false
            System.out.println("Not an boolean (true or false), " + e);
        }
        input.close();

        // wrapper class String
        input =  new Scanner(System.in);
        System.out.print("Enter a String: ");
        try {
            String sampleInputString = input.nextLine();
            System.out.println(sampleInputString);
        } catch (Exception e) { // this may never happen
            System.out.println("Not an String, " + e);
        }
        input.close();
    }
}
ScanPrimitives.main(null);

Enter an integer: 2
Enter a double: 2.0
Enter a boolean: true
Enter a String: hi