Thread: So confused, I need help!

I am taking an intro to java programming class, and I have never done programming before, ever. I'm in a little over my head and my book sucks. My teacher just gave us an assignment after not giving us anything for a month. We need to do the following:

Write a Java program that processes students’ grades.
The program will:
 Repeatedly prompt the user to enter new score or enter -1 to exit
 Assign a grade from F to A to this student and print both the score and
the grade in table with an appropriate header in an output file. The
exact form of the table is left for you to choose
 Count how many A’s, B’s, etc in the class
 Calculate the largest and the lowest score of every grade. For example
the highest A might be 98 and the lowest is 91 and so on
 Calculate the average score of every grade
 Calculate the highest and lowest score in the entire class
 After printing the above mentioned table, report all cumulative results
in the output file with appropriate messages. E.G.
o There were 5 A students in class
o The highest A in class was 99
 An example output is given next page.
Your program should:
 Maintain good indentations that make it readable.
 Include enough comments to demonstrate your understanding of the
different parts of the program and what their functions are.
 Store the output in file called grades.txt
 Be able to deal with the total absence of one or more grades. For
example, in some cases there are no A’s in class
Make sure that the program is your own work. You may be required to have
a discussion about your program with Dr. Ali before your grade for this
homework is finalized.

We have to make a table that looks like this and have the information below it as well.
Score Grade
20 F
98 A
91 A
87 B
85 B
89 B
90 A
62 D
30 F
99 A

There are 4 A student(s) in class
The highest A is 99
The lowest A is 90
The average A is 94.5
++++++++++++++
There are 3 B student(s) in class
The highest B is 89
The lowest B is 85
The average B is 87
++++++++++++++
There are no C students this time
++++++++++++++
There are 1 D student(s) in class
The highest D is 62
The lowest D is 62
The average D is 62
++++++++++++++
There are 2 F student(s) in class
The highest F is 30
The lowest F is 20
The average F is 25
++++++++++++++

To top it all off, it has to print out to a file. I have some of it figured out. I can't figure out the table. Right now the first number I enter is completely ignored and then it doesn't let me enter in any other numbers after the second number is entered and then the rest of the information is wrong.

Here is my (working) code:

// Programming Assingment Grades Grades.java
// grades class uses switch statement to counter letter grades.
import java.util.Scanner; // program uses class Scanner
 
public class Grades
{
	public static void main( String[] args )
	{
		int total = 0; //sum of grades
		int gradeCounter = 0; // number of grades entered
		int aCount = 0; // count of A grades
		int aGrade = 0; // sum of A grades
		int aMax = 0; // max of A grade
		int aMin = 0; // min of A grade
		int bCount = 0; // count of B grades
		int bGrade = 0; // sum of B grades
		int cCount = 0; // count of C grades
		int cGrade = 0; // sum of C grades
		int dCount = 0; // count of D grades
		int dGrade = 0; // sum of D grades
		int fCount = 0; // count of F grades
		int fGrade = 0; // sum of F grades
		int grade; // grade entered by user
 
		Scanner input = new Scanner( System.in );
 
		System.out.printf( "%s\n%s\n",
			"Enter the students grade 0-100",
			"Type -1 when finished" ); // enter grades and terminate when done
			grade = input.nextInt();
 
		while ( grade != -1 )
		{
			grade = input.nextInt();
			total += grade; // add grade to total
			++gradeCounter; // increment number of grades
 
			// letter-grade counter
			if ( grade >= 90 && grade <= 100 )
				{
					grade = 'A';
					++aCount; // increment aCount
				    aGrade += grade; // sum A grades
				}
			else if ( grade >= 80 )
					{
					grade = 'B';
					++bCount; // increment cCount
				    bGrade += grade; // sum B grades
					}
			else if ( grade >= 70 )
					{
					grade = 'C';
					++cCount; // increment cCount
				    cGrade += grade; // sum C grades
					}
			else if ( grade >= 60 )
					{
					grade = 'D';
					++dCount; // increment dCount
				    dGrade += grade; // sum D grades
					}
			else
				{
					grade = 'F';
					++fCount; // increment fCount
				    fGrade += grade; // sum F grades
				}
 
		{
		// display grade table
		System.out.println("----------------------");
		System.out.println("| Score    |Grade    |");
		System.out.println("----------------------");
 
		for ( int g = grade; g <= gradeCounter; grade++)
			System.out.printf("| ", grade);
 
		if ( aCount != 0 )
			{
				int avgA; // A Average
				avgA = aGrade / aCount;
				System.out.printf("There are %d A student(s) in class \n", aCount); // aCount
				System.out.printf("The Average A is %d\n", avgA);
			}
		else
			{
				System.out.printf("There are no A students this time \n");
			}
 
		System.out.print("++++++++++++++ \n");
 
		if ( bCount != 0 )
			{
				int avgB; // B Average
				avgB = bGrade / bCount;
				System.out.printf("There are %d B student(s) in class \n", bCount); // bCount
				System.out.printf("The Average B is %d\n", avgB);
			}
		else
			{
				System.out.printf("There are no B students this time \n");
			}
 
		System.out.print("++++++++++++++ \n");
 
		if ( cCount != 0 )
			{
				int avgC; // C Average
				avgC = cGrade / cCount;
				System.out.printf("There are %d C student(s) in class \n", cCount); // cCount
				System.out.printf("The Average C is %d\n", avgC);
			}
		else
			{
				System.out.printf("There are no C students this time \n");
			}
 
		System.out.print("++++++++++++++ \n");
 
		if ( dCount != 0 )
			{
				int avgD; // D Average
				avgD = dGrade / dCount;
				System.out.printf("There are %d D student(s) in class \n", dCount); // dCount
				System.out.printf("The Average D is %d\n", avgD);
			}
		else
			{
				System.out.printf("There are no D students this time \n");
			}
 
		System.out.print("++++++++++++++ \n");
 
		if ( fCount != 0 )
			{
				int avgF; // F Average
				avgF = fGrade / fCount;
				System.out.printf("There are %d F student(s) in class \n", fCount); // fCount
				System.out.printf("The Average F is %d\n", avgF);
			}
		else
			{
				System.out.printf("There are no F students this time \n");
			}
 
		System.out.print("++++++++++++++ \n");
	}
	}
}
}

And this is what it gives me:

c:\Java>java Grades
Enter the students grade 0-100
Type -1 when finished
1
2
----------------------
| Score |Grade |
----------------------
There are no A students this time
++++++++++++++
There are no B students this time
++++++++++++++
There are no C students this time
++++++++++++++
There are no D students this time
++++++++++++++
There are 1 F student(s) in class
The Average F is 70
++++++++++++++


First I tried to do this with a switch statement but after asking for help all my teacher really said was that I should be using an if/else statement, not a switch statement. I'm super frustrated and really need help.

for others to read your code easier enclose it in (highlight=Java) code here (/highlight) with brackets [ ] instead of ( )