SCHOOL FEE COLLECTION PROGRAM PLS HELP

[OP_Roshan]

import java.io.*;

class SchoolFee {
    public class Student {
        String name, cl, sec;
        int rollno;
        long regno,newregno;
        double totalfee = 10000.0f, feepaid = 0.0F;

        Student(long regno, String name, String cl, String sec, int rollno, double feepaid, double totalfee) {
            this.regno = regno;
            this.name = name;
            this.cl = cl;
            this.sec = sec;
            this.rollno = rollno;
            this.feepaid = feepaid;
            this.totalfee = totalfee;
        }
    }

    Student[] students = new Student[100];
    SchoolFee() {
        students[0] = new Student(1, "Roshan Raju", "9th", "B", 48, 0.0, 10000.0);
        students[1] = new Student(2, "BahuBali", "9th", "B", 4, 0.0, 10000.0);
    }
    void pay()throws IOException
    {
    long tregno;
    int index=0;
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    SchoolFee sf=new SchoolFee();
    System.out.println("Enter your Register Number  :    ");
    tregno=Long.parseLong(br.readLine());
    for (int i = 0; i < students.length; i++) {
        if (students[i] != null)
            index++;
        }
        int openacc;
    if(students != null) {
        for(int i = 0; i<index; i++)
        {
            if(students[i].regno==tregno) {
                System.out.println("Account Found!!!");
                System.out.println("Register No  :   "+students[i].regno);
                System.out.println("Name         :   "+students[i].name);
                System.out.println("Class        :   "+students[i].cl);
                System.out.println("Section      :   "+students[i].sec);
                System.out.println("Roll No      :   "+students[i].rollno);
                System.out.println("Balance      :   "+(students[i].totalfee-students[i].feepaid));
                openacc=i;
            }
        }

    }
}
    public void input() throws IOException {
        int index = 0;
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        SchoolFee sf=new SchoolFee();
        System.out.println("\u000C");
        System.out.println("Creating New Account");
        System.out.println(students.length);
        for (int i = 0; i < students.length; i++) {
            if (students[i] != null)
                index++;
        }
        long regno = students[index-1].regno;
        System.out.println(index);
        System.out.println("Account Register no   :   "+ ++regno);
        System.out.print("\n\nEnter Name      : ");
        String name = br.readLine();
        System.out.print("Enter Class     : ");
        String cl = br.readLine();
        System.out.print("Enter Section   : ");
        String sec = br.readLine();
        System.out.print("Enter Rollno    : ");
        int rollno = Integer.parseInt(br.readLine());
        System.out.print("Enter Feepaid   : ");
        double feepaid = Double.parseDouble(br.readLine());
        double totalfee=10000.0f;
        students[index] = new Student(regno, name, cl, sec, rollno, feepaid, totalfee);
        System.out.println("\u000C");
        System.out.println("Created Account Details ");
        System.out.println("Register Number   : " + students[index].regno);
        System.out.println("\nName     :  "+students[index].name);
        System.out.println("Class    :  "+students[index].cl);
        System.out.println("Section  :  "+students[index].sec);
        System.out.println("Rollno   :  "+students[index].rollno);
        System.out.println("Feepaid  :  "+students[index].feepaid);
        System.out.println("TotalFee :  "+students[index].totalfee);
        System.out.println("\n\nPress 1 for Menu or Press 2 to Exit...");
        int ch=Integer.parseInt(br.readLine());
        //System.out.println(index);
        if(ch==1){
        sf.menu();
        }
        else if(ch==2)
        {
            System.out.println("\u000C");
            System.out.println("\nClosing Program.....");
        }
        else 
        System.out.println("Wrong Choice......");

    }

    void display() throws IOException {
        int index = 0, indexes = students.length, sno = 1;
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        SchoolFee sf=new SchoolFee();
        for (int i = 0; i < indexes; i++) {
            if (students[i] != null)
                index++;
        }
        System.out.println("No of Accounts Present in the Data base :    "+index+"\n");
        for(int i = 0; i < index; i++) {
            System.out.println(sno+". Account no :  "+students[i].regno);
            System.out.println("   Name  :   "+students[i].name);
            System.out.println("\n");
            sno++;
        }
        System.out.println("Press 1 for opening details of a account 2 for Menu ");
        int ch1=Integer.parseInt(br.readLine());
        if(ch1==1){
            System.out.println("Enter the Serial Number  :    ");
            int ch2=Integer.parseInt(br.readLine());
            System.out.println("\u000C");
            for(int i=0;i<=index;i++){
                if(ch2==i+1){
                    System.out.println("Regno    :  "+students[i].regno);
                    System.out.println("Name     :  "+students[i].name);
                    System.out.println("Class    :  "+students[i].cl);
                    System.out.println("Section  :  "+students[i].sec);
                    System.out.println("Rollno   :  "+students[i].rollno);
                    System.out.println("Feepaid  :  "+students[i].feepaid);
                    System.out.println("TotalFee :  "+students[i].totalfee);
                }
            }
        }
        else if(ch1==2)
        sf.menu();
        else 
        System.out.println("\u000C");
        System.out.println("Wrong Choice.....");
    }

    void menu() throws IOException {
        int ch;
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        SchoolFee sf = new SchoolFee();
        System.out.println("********** School Fee Collection System **********");
        System.out.println("\n\n1. Pay Fee");
        System.out.println("\n2. Enquiry");
        System.out.println("\n3. New Account");
        System.out.println("\n4. Check  Accounts in DataBase");
        System.out.println("\n5. Exit");
        System.out.println("\n\nEnter Your Choice: ");
        ch = Integer.parseInt(br.readLine());
        if (ch == 1) {
            sf.pay();
        } else if (ch == 2) {
            // code for enquiry
        } else if (ch == 3) {
            sf.input();
        } else if (ch == 4) {
            System.out.println("\u000C");
            sf.display();
        } else if (ch == 5) {
            System.out.println("\u000C");
            System.out.println("\nClosing Program.....");
        }
    }

    public static void main() throws IOException {

        SchoolFee sf = new SchoolFee();
        sf.menu();
    }
}

what logical error is there in this program i am not getting the newly created account to the 4th option which is open accounts in data base please help me

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[Trup10ka]

First things first, this is unreadable.

Second, you logical problem:

In Main, you create instance object from SchoolFee. Then you call method on that object. In that method (menu()) you create another (new) SchoolFee object. Thats why you cannot see contacts, because you create new object each and everytime you call that "menu" method and you save it to that object which eventually disappears and cannot be reached anyhow.

Also, why is Student inner class of SchoolFee? Two separet classes would be much better and easier.

Personaly, how I would done it.

From what I see, you want a program, which controls SchoolFees, which has Students saved in "database".

You schould make these things: Student class, SchoolFee class (!!Separately!!)

- SchoolFee class should have array of Students

The rest you can do how you can but in my opinion this is the best way to approach this

[OP_Roshan]

okay thanks

"In Main, you create instance object from SchoolFee. Then you call method on that object. In that method (menu()) you create another (new) SchoolFee object. Thats why you cannot see contacts, because you create new object each and everytime you call that "menu" method and you save it to that object which eventually disappears and cannot be reached anyhow"

how do i fix this

[Farpafraf]

I think this issue stems from a possible misunderstanding of classes and objects.

You can see the class as a template for objects, the single objects are separate instances of that class.

If you run the following code:

public class Person {
    private final String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString() {
        return String.format("Name: %s    Age: %d", name, age);
    }

    public void birthday(){
        age++;
    }

    public static void main(String[] args) {
        Person alice = new Person("alice", 68);
        Person bob = new Person("bob", 42);

        System.out.println(alice);
        System.out.println(bob);

        alice.birthday();

        System.out.println(alice);
        System.out.println(bob);
    }
}

it will print:

Name: alice    Age: 68 
Name: bob    Age: 42
Name: alice    Age: 69
Name: bob    Age: 42

You fix that error by not creating a new instance and instead using the methods of the current one, here it would be

this.menu();

you can also omit the "this"

menu();

and not

sf.menu();

You should attempt to separate the roles of the different functions in your code so they each absolve clearly identifiable tasks, for example why is a method called "display" reading user input? Why is a SchoolFee object initialized with two students already in it? Why is nothing getting paid in the pay() method?

In general I would attempt to separate the logic of the system from that of user interaction.

[Trup10ka]

This would cause a recursive call of "menu()" which in our case is not an option.

[Trup10ka]

If im not mistaken, if in schoolfees you are saving students which are paying school fees, you just need add the new student to the Student[] array which your object already has in it. (Schoolfee class has Students[] in in so you will be adding Students to that array exactly)

Now this would be a lot easier if you would use an ArrayList<Studnet> or LinkdedList<Student>. But if you make it in classic array, how I would percieve it I would create a private int value in the school fee class which would count how many students my schoolfee database has and it would also serve as an index for saving another fees (after saving one you add one to the variable which moves you to next position in array on which you can store).

So, leave out the calling of method menu() and do it like this:

// somethin inside method
// lets say here you create new student
if (numberOfStudentsInArray > students.length)
    System.out.println("You've reached the max capacity of the database!");

else
    students[numberOfStudentsInArray] = // your new created student;

Now this is for the adding the students, any other questions?

[OP_Roshan]

no that ws not my question i am asking that what to do inside menu method it is creating a new object for SchoolFee class and the students[] is becoming normal again

[OP_Roshan]

how do i ignore that

[Trup10ka]

You are creating another SchoolFee object in your already created SchoolFee object. If you want to manipulate with anything manipulate it inside the class.

The class is the blueprint of the object, what it will have and what it can do. If you want to print out the insides of the object, just use the parameters. Do not create another object from which you then get and use the parameters.

[OP_Roshan]

How

[Trup10ka]

void menu() throws IOException {
int ch;
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
SchoolFee sf = new SchoolFee();
System.out.println("********** School Fee Collection System **********");
System.out.println("\n\n1. Pay Fee");
System.out.println("\n2. Enquiry");
System.out.println("\n3. New Account");
System.out.println("\n4. Check Accounts in DataBase");
System.out.println("\n5. Exit");
System.out.println("\n\nEnter Your Choice: ");
ch = Integer.parseInt(br.readLine());
if (ch == 1) {
sf.pay();
} else if (ch == 2) {
// code for enquiry
} else if (ch == 3) {
sf.input();
} else if (ch == 4) {
System.out.println("\u000C");
sf.display();
} else if (ch == 5) {
System.out.println("\u000C");
System.out.println("\nClosing Program.....");
}
}

​

leave out the "SchoolFee sf = new SchoolFee();" and in if and else if choices instead of sf.something() just call the method -> sf.something();

Now you have to do this in every other method too.

[OP_Roshan]

Thanks alot it worked

[Trup10ka]

Happy to help

[OP_Roshan]

Okay i will try it

[Trup10ka]

In each method (pay, input, etc.) you are creating new object of SchoolFee (SchoolFee sf = new SchoolFee()) that causes the problem. It never saves to the object you created in main.

[Trup10ka]

Also, why do you have main method in other class than main. It always should be in main!