Java Object Oriented Grades Program

[Ben Peer]

Basically this is it, Friday I have this program due. I've been trying but cannot figure it out so I'm seeking help.

This is what the assignment is:

Write a OOP program for your Computer Science teacher that can be used to calculate final grades in Computer Science. The teacher uses the following grade items:
1. five quizzes, each graded out of 10 points
2. a midterm exam graded out of 100 points
3. a final exam, graded out of 100 points

The defining class should contain a constructor with parameters for student’s name, test marks, midterm mark and final exam.

The defining class will have one method to calculate a student’s numeric grade and their final letter grade. Grade items will be weighted as follows:

1. final exam counts for 25% of the final mark
2. midterm counts for 25%
3. five quizzes together count for a total of 50%.

The final letter grade will be determined as follows:

1. 90 or more is an A
2. 80 or more(but less than 90) is a B
3. 70 or more(but less than 80) is a C
4. 60 or more(but less than 70) is a D
5. below 60 is an F

The method should output both the calculated, numeric grade and the final letter grade.

Write a tester class to test your application. Use the constructor to create five students and initialize the instance variables for each student. Invoke the method to calculate the numeric grade and final letter grade for each student. Output each student’s name and show their numeric grade and letter grade.


This Is What I've Done

    

//This program calculates and displays the grades of a student for the computer science course

//the second class
class Grades
{
		// variables
		String studentName;
		int testMarks = 0;
		int midtermMark = 0;
		int finalExam = 0;
	
		//constructor with 4 parameters to initialize the variables
		double Basketball(String studentName, int quizMark, int midtermMark, int finalExam)
		{
		studentName = studentName;
		quizMark = quizMark;
		midtermMark = midtermMark;
		finalExam = finalExam;
		}

		String letterGrade;
		double finalMark = ((finalExam * .25) + (midtermMark * .25) + (quizMark * .50));

		//calculate method
		String calculate()
		{


			if (finalMark <= 90)
				{
				return letterGrade = 'A';
				}
			if (finalMark <= 80)
				{
				return letterGrade = 'B';
				}
			if (finalMark <= 70)
				{
				return letterGrade = 'C';
				}
			if (finalMark <= 60)
				{
				return letterGrade = 'D';
				}
			if (finalMark > 60)
				{
				return letterGrade = 'F';
				}

			System.out.println( "Student name: " + studentName );     
			System.out.println( "Quiz score: " + quizMark );      
			System.out.println( "Midterm Exam score: " + midtermMark );    
			System.out.println( "Final Exam score: " + finalExam );  
			System.out.println( "Your final grade is: " + finalMark ); 
		}

}

class GradesTester //the main class whose sole purpose is to test the second class, the Grades  class
{
	//starts program
	public static void main(String[] args)
	{		
		//constructs a Grades object also known as creating an instance of the Grades class and initializes the variables		
		Grades student1 = New Grades ("Marcus Banks", 78, 86, 87);
		Grades student2 = New Grades ("Billy Kid", 74, 89, 78);
		Grades student3 = New Grades ("William Gates", 84, 90, 89);
		Grades student4 = New Grades ("Wilber Cumberbottom", 25, 35, 44);
		Grades student5 = New Grades ("Anita Bath", 100, 100, 100);

		student1.calculate();
		student2.calculate();
		student3.calculate();
		student4.calculate();
		student5.calculate();
	}
}

I keep getting error messages and I just really need help to get it to compile properly then i can at least start getting the bugs out. any help is appreciated.

Thanks if you can help.

[Nicola Garofalo]

Begin with putting lines 23 and 24 inside a method (calculate() for example)

[Jan Cumps]

Welcome to JavaRanch, Ben.

Ben Peer wrote:...I keep getting error messages and I just really need help to get it to compile properly then i can at least start getting the bugs out. ....

What are these error messages?

[Ben Peer]

at my constructor

Error : ';' expected
Grades student1 = New Grades("Marcus Banks", 78, 86, 87);
                                   ^

Error : ';' expected Grades student1 = New Grades("Marcus Banks", 78, 86, 87); ^



it says with the ^ under the G in Grades that ';' is expected (for all of them student1 to student5)


also i dont know how to reply on these :S ??

[Nicola Garofalo]

New? java is case sensitive Ben.
Try with

new

[Ben Peer]

I've tried that and it didn't help any still got error messages

[Nicola Garofalo]

Sure it does.
Look at your constructor. Where is it?

[Ben Peer]

in the

public static void main(String[] args)  

and the GradesTester class

should i move it out of

public static void main(String[] args)  

[Nicola Garofalo]

You wrote

Grades student1 = New Grades ("Marcus Banks", 78, 86, 87); 

but in class Grades where's the constructor that takes 4 arguments (String,int,int,int) ?

write it in class Grades, let me know

[Ben Peer]

C:\j2sdk1.4.2_19\bin>javac GradesTest.java
GradesTest.java:32: cannot resolve symbol
symbol  : variable quizMark
location: class Grades
                double finalMark = ((finalExam * .25) + (midtermMark * .25) + (q
uizMark * .50));
                                                                               ^

GradesTest.java:41: incompatible types
found   : char
required: java.lang.String
                                return letterGrade = 'A';
                                                     ^
GradesTest.java:45: incompatible types
found   : char
required: java.lang.String
                                return letterGrade = 'B';
                                                     ^
GradesTest.java:49: incompatible types
found   : char
required: java.lang.String
                                return letterGrade = 'C';
                                                     ^
GradesTest.java:53: incompatible types
found   : char
required: java.lang.String
                                return letterGrade = 'D';
                                                     ^
GradesTest.java:57: incompatible types
found   : char
required: java.lang.String
                                return letterGrade = 'F';
                                                     ^
GradesTest.java:61: cannot resolve symbol
symbol  : variable quizMark
location: class Grades
                        System.out.println( "Quiz score: " + quizMark );
                                                             ^
GradesTest.java:77: cannot resolve symbol
symbol  : constructor Grades (java.lang.String,int,int,int)
location: class Grades
                Grades student1 = new Grades("Marcus Banks", 78, 86, 87);
                                  ^
GradesTest.java:78: cannot resolve symbol
symbol  : constructor Grades (java.lang.String,int,int,int)
location: class Grades
                Grades student2 = new Grades("Billy Kid", 74, 89, 78);
                                  ^
GradesTest.java:79: cannot resolve symbol
symbol  : constructor Grades (java.lang.String,int,int,int)
location: class Grades
                Grades student3 = new Grades("William Gates", 84, 90, 89);
                                  ^
GradesTest.java:80: cannot resolve symbol
symbol  : constructor Grades (java.lang.String,int,int,int)
location: class Grades
                Grades student4 = new Grades("Wilber Cumberbottom", 25, 35, 44);

                                  ^
GradesTest.java:81: cannot resolve symbol
symbol  : constructor Grades (java.lang.String,int,int,int)
location: class Grades
                Grades student5 = new Grades("Anita Bath", 100, 100, 100);
                                  ^
12 errors

this is what i get with the constructor thing in the Grades class instead of the Gradestester class

[Nicola Garofalo]

The lines

       Grades student1 =  new Grades ("Marcus Banks", 78, 86, 87);
        Grades student2 = new Grades ("Billy Kid", 74, 89, 78);  
        Grades student3 = new Grades ("William Gates", 84, 90, 89);  
        Grades student4 = new Grades ("Wilber Cumberbottom", 25, 35, 44);  
        Grades student5 = new Grades ("Anita Bath", 100, 100, 100);

has to stay where they were. You can place them back where you cut them.

You should write in class Grades the corresponding constructor, because Grades does not know what a call to
Grades("Marcus",78,86,87) is

in class Grades then write the constructor.

In Italy now is 0:30 and tomorrow i need to wake up early...but you will surely find other people ready to help you. If you don't i will tomorrow.

The last thing. Look at your code. You don't need Basketballs now...you are doing your homework. You need just Grades.

Grades(String studentName, int quizMark, int midtermMark, int finalExam){
 //put the initialization code here
}

[Ben Peer]

sorry for keeping you up im just starting from scratch

[Nicola Garofalo]

It's ok, don't worry. I was just telling you that you wouldn't have found me online for some hours

Well, how's your code? Did you solve your problems?

If not, can you please post it again with the changes you made?

[Campbell Ritchie]

Brandon Armstrong,
Your post was moved to a new topic.