Java program for student mark list using inheritance - java code examples with output
Java OOP Tutorial
Build a Student Mark List in Java Using Inheritance
This guide walks through designing a console-based Java application that captures marks for multiple students, calculates their totals, and prints a formatted report. You will apply single inheritance, encapsulation, and clean code practices to keep the workflow easy to extend.
Objective: Build a reusable base class for shared behaviours (input/output) and extend it with a student-specific subclass that stores marks and totals.
Key Concepts
- Single inheritance
- Array storage
- Formatted console output
Prerequisites
- Java 8 or newer
- Basic OOP knowledge
- Terminal/command prompt access
Deliverables
A `StudentReport` program that collects marks for n students, calculates totals, and prints a tabular mark list.
Designing the Class Hierarchy
Base Class: `MarkSheet`
Handles common tasks such as reading input, storing student data, and printing formatted headers. Methods include `captureStudent()` and `printTable()`.
Derived Class: `StudentReport`
Extends `MarkSheet` to add application flow—collecting the number of students, looping through entries, calculating totals, and triggering the final print.
Complete Java Implementation
The following code uses `Scanner` for input and keeps responsibilities separated across classes. Use it as a starting point for experimenting with grading rules or exporting data.
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
class MarkSheet {
static class Student {
String name;
int[] marks;
int total;
Student(String name, int subjectCount) {
this.name = name;
this.marks = new int[subjectCount];
}
}
protected final Scanner scanner = new Scanner(System.in);
protected final List<Student> students = new ArrayList<>();
protected final int subjectCount;
MarkSheet(int subjectCount) {
this.subjectCount = subjectCount;
}
protected void captureStudent() {
System.out.print("Student name: ");
String name = scanner.nextLine().trim();
Student student = new Student(name, subjectCount);
for (int i = 0; i < subjectCount; i++) {
System.out.printf("Subject %d mark: ", i + 1);
student.marks[i] = Integer.parseInt(scanner.nextLine().trim());
student.total += student.marks[i];
}
students.add(student);
}
protected void printTable() {
System.out.println("============================================================");
System.out.printf("%-4s %-18s", "No", "Student Name");
for (int i = 0; i < subjectCount; i++) {
System.out.printf(" Sub%-2d", i + 1);
}
System.out.printf(" Total%n");
System.out.println("============================================================");
int index = 1;
for (Student student : students) {
System.out.printf("%-4d %-18s", index++, student.name);
for (int mark : student.marks) {
System.out.printf(" %-6d", mark);
}
System.out.printf(" %-6d%n", student.total);
}
System.out.println("============================================================");
}
}
public class StudentReport extends MarkSheet {
public StudentReport(int subjectCount) {
super(subjectCount);
}
public void run() {
System.out.print("How many students? ");
int numberOfStudents = Integer.parseInt(scanner.nextLine().trim());
for (int i = 0; i < numberOfStudents; i++) {
System.out.printf("%nEnter details for student %d%n", i + 1);
captureStudent();
}
System.out.println();
printTable();
}
public static void main(String[] args) {
int subjectCount = 5; // Adjust as needed
StudentReport report = new StudentReport(subjectCount);
report.run();
}
}Sample Console Output
How many students? 2 Enter details for student 1 Student name: Ankaj Subject 1 mark: 8 Subject 2 mark: 9 Subject 3 mark: 6 Subject 4 mark: 7 Subject 5 mark: 9 Enter details for student 2 Student name: Anmol Subject 1 mark: 9 Subject 2 mark: 6 Subject 3 mark: 7 Subject 4 mark: 8 Subject 5 mark: 9 ============================================================ No Student Name Sub1 Sub2 Sub3 Sub4 Sub5 Total ============================================================ 1 Ankaj 8 9 6 7 9 39 2 Anmol 9 6 7 8 9 39 ============================================================
Suggested Enhancements
Feature Ideas
- Calculate averages and grades
- Export reports to CSV or PDF
- Add validation for mark ranges
Common Pitfalls
- Mixing `Scanner.nextInt()` and `nextLine()` without consuming newline characters
- Hard-coding subject counts across multiple methods
- Ignoring encapsulation—keep student details private