Gain insights into Java programming by exploring conditional statements, loops, math, logic, inheritance, generics, and arraylists, to become an intermediate Java developer.

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You'll start with a simple hello world program and proceed to cover common concepts such as Conditional Statements, Loop Statements, Math, and Logic in Java, before moving on to more advanced concepts like Inheritance, Generics, and ArrayLists, along with much more.

By the time you're done, you'll be an intermediate level Java developer, ready to take on your own projects.

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class gpaHelper{

    public static double letterToGPA (String grade) {
        double answer;

        switch (grade) {
            case "A+":
            case "A":
                answer = 4;
                break;

            case "A-":
                answer = 3.7;
                break;

            case "B+":
                answer = 3.3;
                break;

            case "B":
                answer = 3;
                break;

            case "B-":
                answer = 2.8;
                break;

            case "C+":
                answer = 2.5;
                break;

            case "C":
                answer = 2.0;
                break;

            case "C-":
                answer = 1.8;
                break;

            case "D":
                answer = 1.5;
                break;

            case "F":
                answer = 0;
                break;

            default:
                answer = -1;
        }

        return answer;
    }
 public static void main( String args[] ) {
        System.out.println("Grade A: " + letterToGPA("A"));
        System.out.println("Grade D: " + letterToGPA("D"));
        System.out.println("Grade L: " + letterToGPA("L"));
    }
    
}

# Understanding your Code

Line 3
* The method `letterToGPA` is declared **static** so it can be called without creating an object.

* The method takes in a **single** argument which is of type *String* and return *double* value in the output. 

Line 4: A **double** type variable `answer` is declared which will store the final GPA point.

> **Note:** We have chosen to use `switch` statements instead of an if condition for code brevity. We can also use `if-then-else` block.

Lines 6-46:
* This statement is the start of the **switch** statement block.
* The argument in the round brackets, `()`, is the variable which will be equated in the following *cases*. We check the value of `grade` against each case until the `grade` matches the particular case value. Once the value matches, we will set the value of `answer` accordingly and come out of the loop immediately.




Lines 48-49
* This is a special *case*.
* The **default** case states that provided that **no other** condition is met, this is what should be done.
* In the problem statement above, we are told that if **any other** grade is given, the output should be `-1` so that an incorrect grade can be detected.
* This can be seen in Line 49 where the variable **answer** is equated to `-1`.


Line 53

* The `answer` variable is returned to the main method calling it.

In this review, solution of the challenge 'Letter Grade to GPA' from the previous lesson is provided.

Getting Started with Java!

Variables & User Input

Simple Maths & Logic

Strings and String Processing

Conditional Statements

Loops

Methods

Arrays

Classes and Inheritance

Generics

ArrayLists

Java Exam

Solution Review: Letter Grade to GPA

Solution: Is your GPA correct?