Primitives Notes

Python

weakly type language
don't have to specifiy type of data, ie double quote for string

Java

strongy type language
requires you to think about it more and which type of data it is

Java C and Java

Java C executes then Java executes then the program runs

Data Tyes

Data types with a captial letter are primitives are lowercase
Data types with a lowercase letter are wrappers
Primitives are just the numbers assigned to memory
primitives are built in
Wrappers are classes and have methods, getters, and setters
has built in code with it that can do more stuff
to compare two strings you can use ".equals"
methods are code associated with the type
string is basically an object
not built in has to be declared

Primitive Hacks

Define in a class the following data types
- Demonstrate use of Primitives: int, double, boolean, string

public class Primitives {
  public static void main(String[] args) {
    int x = 5;
    double z = 9.88;
    boolean w = true;
    System.out.println(x);
    System.out.println(z);
    System.out.println(w);
    }
}
Primitives.main(null);

5
9.88
true

Demonstrate use of Wrapper Class object: String

Perform arithmetic expressions and assignment in a program code Code.org Lesson

public class Math{
    public static void main(String[] args){
        int a = 3;
        int b = 10;
        double c = 2.5;
        c = 2 * a - 15 / b + c;
        System.out.println(c);
    }
}
Math.main(null);

7.5

Describe in comments how each data type choice is appropriate to application
Determine what is result in a variable as a result of an data type and expression

import java.util.Scanner; // Import the Scanner class

public class TemperatureConverter { // Defining the main
    public static void main(String[] arg){
        Scanner inputTemp = new Scanner(System.in);
        
        System.out.println("Enter a temperature");

        int tempInt = inputTemp.nextInt(); // Stores as an integer. 

        Scanner tempTypeinput = new Scanner(System.in);
        System.out.println("Is it in Fahrenheit or Celsius. Type C for Celsius or F for Fahrenheit.");
        String tempType = tempTypeinput.nextLine(); // Stores as a string

        if (tempType.equals("C")){
           double convertedTemp = tempInt * 1.8; // Double is appropriate here because decimals are needed
           double convertedTempF = convertedTemp + 32;
           System.out.println("Celsius: " + tempInt + "°C and Fahrenheit: " + convertedTempF + "°F");
        } 
        if (tempType.equals("F")) {
           double convertedTemp = tempInt - 32;
           double convertedTempC = convertedTemp/1.8; // Double is appropriate here because decimals are needed
           System.out.println("Fahrenheit: " + tempInt + "°F and Celsius: " + convertedTempC + "°C");
        }
    }
}

TemperatureConverter.main(null);

Enter a temperature
Is it in Fahrenheit or Celsius. Type C for Celsius or F for Fahrenheit.
Celsius: 0°C and Fahrenheit: 32.0°F

Perform an arithmetic expressions that uses casting, add comments that show how it produces desired results

// Casting temporary treats on variable of a data type as another data type

public class Math{
    public static void main(String[] args) {
        double a = 6.5 + 5;
        System.out.println(a);
        System.out.println((int)(a));

        double number = 11.0/4;
        int roundNumber = (int)(number+0.5);
        System.out.println(number);
        System.out.println(roundNumber);

        Scanner inputNumber = new Scanner(System.in);
        
        System.out.println("Enter a decimal to be rounded");

        double tobeRounded = inputNumber.nextDouble(); // Stores as an double.
        
        System.out.println((int)(tobeRounded + 0.5));
        
    }
}
Math.main(null)

11.5
11
2.75
3
Enter a decimal to be rounded
7