Question

Java

This application will be menu driven.

The application should allow:

1. Collect student information and store it in a binary data file. Each student is identified by an unique ID.  
The user should be able to view/edit an existing student. Do not allow the user to edit student ID.

2. Collect Course information and store it in a separate data file. Each course is identified by an unique ID.
The user should be able to view/edit an existing course information.
User is not allowed to edit the key field such as Course ID.

3. Collect Enrollment information.
Here you allow the user to enroll students to courses.
You make sure that the user types valid student id and course ID.
You display the student and course information in the window.
You will have to store enrollment information in a separate binary file.
This file may contain the course, student ID, Year and semester information.

4. Grade Management, such as Add grades, View Grades.
You will allow the user to enter student ID, year, Semester, course ID, and the grade.
The user should be above to view/edit the grades.

You can create a menu driven interface to select the above options.

Answer 1

import java.io.*;

//package com.farenda.java.io;

import java.io.*;

import java.io.BufferedOutputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.nio.charset.StandardCharsets;

class Student

{

String studentId;

String name;

String phoneNo;

Student(String id,String name,String phone)

{

this.studentId=id;

this.name=name;

this.phoneNo=phone;

}

public String getId()

{

return studentId;

}

public String getName()

{

return name;

}

public String getPhoneNo()

{

return phoneNo;

}

public void setName(String name)

{

this.name=name;

}

public void setPhoneNumber(String no)

{

this.phoneNo=no;

}

public String toString()

{

return "\n\tStudent Id: "+studentId+"\n\tStudent Name: "+name+"\n\tPhoneNo: "+phoneNo+"\n";

}

private static byte[] getUtf8Bytes(String s) {

// Always specify encoding and not rely on default!

return s.getBytes(StandardCharsets.UTF_8);

}

}

//This is Course file

class Course

{

String courseId;

String courseName;

Course(String cid,String cname)

{

this.courseId=cid;

this.courseName=cname;

}

public String getCourseId()

{

return courseId;

}

public String getCourseName()

{

return courseName;

}

public void setCourseName(String cname)

{

this.courseName=cname;

}

public String toString()

{

return "CourseId: "+courseId+"\tCourseName: "+courseName+"\n";

}

}

//this is Enrollment class. Here you will be find main method also

import java.io.*;

import java.nio.ByteBuffer;

public class Enrollment

{

Student newStudent;

Course newCourse;

String year;

String semester;

float grade;

Enrollment(Student s,Course c,String y,String sem)

{

this.newStudent=s;

this.newCourse=c;

this.year=y;

this.semester=sem;

}

public void setGrade(float gr)

{

this.grade=gr;

}

public float getGrade()

{

return grade;

}

public String toString()

{

return "Student Info: "+newStudent+"\n\tCourseInfo: "+newCourse+"\n\tYear: "+year+

"\n\tSemester"+semester+"\n\tGrade: "+grade+"\n";

}

public void writeStudentFile()throws IOException

{

OutputStream output = null;

try {

byte[] result =newStudent.toString().getBytes();

//result= ()newStudent.toString();

output = new BufferedOutputStream(new FileOutputStream("student_out.dat"));

//OutputStream output=openFile("data.dat");

output.write(result,0,result.length);

//output.write(getUtf8Bytes(studentId+"\t"+name+"\t"+phoneNo+"\n"));

//output.writeBytes(studentId+"\t"+name+"\t"+phoneNo+"\n");

}

finally {

output.close();

}

}

public static byte[] toByteArray(float value) {

byte[] bytes = new byte[4];

ByteBuffer.wrap(bytes).putFloat(value);

return bytes;

}

public void writeEnrollmentFile()throws IOException

{

OutputStream output = null;

try {

byte[] id =newStudent.getId().getBytes();

byte [] cid=newCourse.getCourseId().getBytes();

byte[] ye=year.getBytes();

byte[] se=semester.getBytes();

byte[] bytes = toByteArray(grade);

//result= ()newStudent.toString();

output = new BufferedOutputStream(new FileOutputStream("Enrollment_out.dat"));

//OutputStream output=openFile("data.dat");

output.write(id,0,id.length);

output.write(cid,0,cid.length);

output.write(ye,0,ye.length);

output.write(se,0,se.length);

output.write(bytes,0,bytes.length);

//output.write(getUtf8Bytes(studentId+"\t"+name+"\t"+phoneNo+"\n"));

//output.writeBytes(studentId+"\t"+name+"\t"+phoneNo+"\n");

}

finally {

output.close();

}

}

public void writeCourseFile()throws IOException

{

OutputStream output = null;

try {

byte[] result =newCourse.toString().getBytes();

//result= ()newStudent.toString();

output = new BufferedOutputStream(new FileOutputStream("course_out.dat"));

//OutputStream output=openFile("data.dat");

output.write(result,0,result.length);

//output.write(getUtf8Bytes(studentId+"\t"+name+"\t"+phoneNo+"\n"));

//output.writeBytes(studentId+"\t"+name+"\t"+phoneNo+"\n");

}

finally {

output.close();

}

}

public static void main(String args[])throws IOException

{

int opt;

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

System.out.println("\n------ Student Course Enrollment System------\n");

do

{

System.out.println("-----Collect Student Info-----");

System.out.println("Enter Student Id: ");

String id=br.readLine();

System.out.println("Enter Student Name: ");

String name=br.readLine();

System.out.println("Enter Student PhoneNum: ");

String phone=br.readLine();

Student s=new Student(id,name,phone);

System.out.println("\n------Enter Course Info-------\n");

System.out.println("Enter Course Id: ");

String cid=br.readLine();

System.out.println("Enter Course Name: ");

String cn=br.readLine();

Course co=new Course(cid,cn);

System.out.println("Enter the Current Year: ");

String yr=br.readLine();

System.out.println("Enter the Semester slot: ");

String seme=br.readLine();

Enrollment fresh=new Enrollment(s,co,yr,seme);

System.out.println("Enter the Grade points: ");

float gr=Float.parseFloat(br.readLine());

fresh.setGrade(gr);

fresh.writeCourseFile(); //Writing data into course_out.dat file

fresh.writeStudentFile(); //writing data into student_out.dat file

fresh.writeEnrollmentFile(); //writing data into enrollment_out.dat file

System.out.println(fresh);

System.out.println("Do you want to add another Enrollment? Press 1 for Yes\t 2 for No:\t");

opt=Integer.parseInt(br.readLine());

}while(opt!=2);

}

}