Java For Loop - Exercise

Create a command-line application named GradePointAverage that calculates the grade-point average of the letter grades represented by a string that the user supplies as a command-line argument.
Probably the easiest way to begin this exercise is to start with your GradePoints program. Your solution to this exercise will use the static method gradePoints() that you created previously.
Additionally, you will need to create another static method gradePointAverage() that accepts a String reference as parameter. The characters contained in this String object will represent a collection of letter grades. The gradePointAverage() method should return a double which represents the grade-point average (GPA) of the letter grades. For example, after the following code executes, the variable result contains 3.25:

double result = gradePointAverage("ABAC");

In your gradePointAverage() method you will need to loop through the characters contained in the String object. There are two methods provided by the String class that you will find useful. The method length() returns the number of characters contained in a String. The method charAt(int) returns the char at the specified index. The indexes for the chars contained in a String object begin with 0. Here's an example of some code that uses both of these methods:

String s = "Java rocks!"
System.out.println("The length of s is " + s.length());
System.out.println("The third char of s is " + s.charAt(2));

public static void main(String[] args) {
if (args.length != 1) {
System.out.println("Usage: java Grades GradeString");
System.exit(0);
}
// Use gradePointAverage() to calculate the GPA
// of the grades represented in args[0]
}

In the text box below, cut and paste the source code for the GradePointAverage application. Click the Submit button to submit your code.