Don't know how to have java remember Overall total and add it

[Nicholas Andrade]

code:

import java.util.*;
import java.util.Scanner;
import java.text.*;

class Student1
{
    public static void main(String[] args){

		System.out.println("Welcome to The Magellan School for Sailing!");
        Scanner input=new Scanner(System.in);
        System.out.print("Enter Student Number: ");
        int id=input.nextInt();
while
(id<500)
{
System.out.print("Invalid Student Number (below 500): ");
id=input.nextInt();
}
while
(id>5000)
{
System.out.print("Invalid Student Number (above 5000): ");
id=input.nextInt();
}

        System.out.print("Enter Surname: ");
        String surname=input.next();
        System.out.print("Enter First Name: ");
        String name=input.next();
        System.out.print("How many Subjects are you calculating: ");
		int subject_count = input.nextInt();
		int count=0;
		for(count =1; count <= subject_count; count++)

        {


		System.out.println("Subject: 1. Boat Maintenance");
		System.out.println("         2. Basic Sail Control");
		System.out.println("         3. Blue-water Navigation");
		System.out.println("         4. Chart reading");
	    System.out.println("         5. Laws & Customs of the sea");
	    System.out.println();
	    System.out.print("Subject Choice: ");
	    String subject=input.next();


	     System.out.print("How many assignments shall I calculate?: ");
	       int cal=input.nextInt();
           int hw[]=new int[cal];
           int exam[]=new int[cal];
		   int sum=0;
		   int sum2=0;
		   for(int i=0;i<hw.length;i++)
		   for(int l=0;i<exam.length;i++){
		   System.out.print("Homework mark for assignment: ");
		   hw[i]=input.nextInt();
		   System.out.print("Examination mark for assignment: ");
		   exam[l]=input.nextInt();
		   sum+=hw[i];
		   sum2+=exam[l];

          }
           System.out.println("****************************************************");
           System.out.print("Results for "+name );
           System.out.print( surname );
           System.out.print(", Student Number: ");
           System.out.println( id );

         switch (subject)
		 		   {
		 		   case "1" :
		 		   System.out.println("Boat Maintenance");
		 		   break;
		 		   case "2" :
		 		   System.out.println("Basic Sail Control");
		 		   break;
		 		   case "3" :
		 		   System.out.println("Blue-water Navigation");
		 		   break;
		 		   case "4" :
		 		   System.out.println("Chart reading");
		 		   break;
		 		   case "5" :
		 		   System.out.println("Laws & Customs of the sea");
		 		   break;
}

       double averagehw=sum/(hw.length);
       System.out.println("Average Homework mark: "+averagehw);
       double averageexam=sum2/(exam.length);
       System.out.println("Average Exam mark: "+averageexam);
       double overall=0;
       overall=0.2*averagehw+0.8*averageexam;
       System.out.println("Overall Mark: "+overall);

       String grade="";
	           if(overall<40){
	               grade="Fail!";
	           }
			   else if((overall>=35) && (overall<40)){
				   	grade="E!";
			   }
			   else if((overall>=40) && (overall<=50)){
	               grade="D!";
	           }
	           else if((overall>=50) && (overall<60)){
	               grade="C!";
	           }
	           else if((overall>=60) && (overall<74)){
	               grade="B!";
	           }
	           else if((overall>=75) && (overall<=100)){
	               grade="A!";
        }
       System.out.println("Grade: "+grade);
       System.out.println();

}

	}
}

I don't know how to get the overall total to calculate and give an overall total.. i don't know if i did it wrong i dont know what to do

[Campbell Ritchie]

Welcome to the Ranch

You will have problems with that code because you aren't createing objects. You have got one method, which is far too large, and should me made into lots of little methods. You should have some sort of class for Module or something like that, which has totals for all the students, and you add to it as each student is registered.

[Nicholas Andrade]

Campbell Ritchie wrote:Welcome to the Ranch

You will have problems with that code because you aren't createing objects. You have got one method, which is far too large, and should me made into lots of little methods. You should have some sort of class for Module or something like that, which has totals for all the students, and you add to it as each student is registered.

Thank you Campbell.. I'm new to this an I'm totally lost.. Can you help guide me in the right direction ??

[Anayonkar Shivalkar]

Hi Nicholas,

Welcome to CodeRanch!

As Campbell has already mentioned, you need to make the code modular.

Apart from that, I haven't gone through all the code, but it will be much helpful if you TellTheDetails(<-click) - that is - what is the input you gave, what was the expected output, what is actual output etc.

Also, you can try and put some extra print statements at intermediate steps (e.g. after calculating the sum etc.) to understand in which area the code is going wrong.

I hope this helps.

[Campbell Ritchie]

You start small. Get the student class working (maybe) and try it out with a Student Demo (That brings back memories of the 1960s ‍) class. Start with Student having one field only, and add fields as your tests appear correct. Try the first, the add the id number. Then get a Module/Course field.
You can forget StudentDemo whenever the tests are successful. Forget about the rest of the app until you have Student working and add it later.

[Nicholas Andrade]

Thanks guys.. will give it another shot an see how I end up! Thanks again

[Campbell Ritchie]

You're welcome
Do show us what you have got, when you have some new code.

[Nicholas Andrade]

my fellow coders!! my question to you is how do you define multiple methods within java... i'm a total newie with this!! kinda feel stupid i enjoy the challenge tho

[Anayonkar Shivalkar]

Hi Nicholas,

It seems that you are new to object oriented concepts. I would recommend to go through those concepts (e.g. Head First Object Oriented Analysis and Design) or a decent Java book which covers the basics (e.g. Head First Java).

Short answer to your question:
You can define multiple methods in a class. Then, you can create object of the class to invoke those methods.

Of course, there are more rules to it (e.g. you cannot invoke private methods over the instance directly etc.) and going through the resources I've mentioned should help.

[Campbell Ritchie]

Like this:-

public class Foo
{
   private int i;
 . . .
   public void bar()
   {
      System.out.println(i);
   }

   public void baz(int j)
   {
      System.out.println(i + j);
   }

   public int biz(int j)
   {
      return i * j;
   }
}

And if you can't think of more useful methods that that …

[Nicholas Andrade]

Campbell, i was actually just looking at a video on you tube explaining it ... you guys are great help! i'm glad i found this forum! i will attempt coding again and see... Thank you again!

[Campbell Ritchie]

You're welcome
Some videos on YouTube are really good, others not so. Don't “try” any coding. Write down what you want on paper, then write the code. Do it a tiny bit at a time.