CGPA Calculator REST API

A Spring Boot REST API for calculating Cumulative Grade Point Average (CGPA) based on course records.

Features

• Create, read, update, and delete course records
• Automatic grade-to-grade-point conversion
• Calculate overall CGPA across all semesters
• Calculate semester-specific GPA
• Filter courses by semester

Grade Point System

Grade	Grade Points
A	5
B	4
C	3
D	2
E	1
F	0

CGPA Calculation Formula

CGPA = (Sum of (Unit × Grade Point)) / (Sum of Units)

Technologies Used

• Java 17
• Spring Boot 3.1.5
• Spring Data JPA
• Lombok
• Maven

Project Structure

rest-grpc-demo/
│
├── pom.xml
│
└── src/
    └── main/
        ├── java/
        │   └── com/
        │       └── example/
        │           ├── Application.java
        │           │
        │           └── cgpa/
        │               ├── model/
        │               │   └── CourseRecord.java
        │               │
        │               ├── repository/
        │               │   └── CourseRecordRepository.java
        │               │
        │               ├── dto/
        │               │   └── CGPAResponse.java
        │               │
        │               ├── service/
        │               │   └── CourseRecordService.java
        │               │
        │               └── controller/
        │                   └── CourseRecordController.java
        │
        └── resources/
            └── application.properties

Getting Started

Prerequisites

• Java 17 or higher
• Maven 3.6+

Build and Run

Install "mvn" on Ubuntu(WSL):

sudo apt update
sudo apt install maven - #this is the namme of the package

# Check the Version for confirmation
mvn -version

# Build the project
mvn clean install

# Run the application
mvn spring-boot:run

The application will start on http://localhost:8080

API Endpoints

Course Records

Method	Endpoint	Description
POST	/api/courses	Create a new course record
GET	/api/courses	Get all course records
GET	/api/courses/{id}	Get course record by ID
GET	/api/courses/semester/{semester}	Get courses by semester
PUT	/api/courses/{id}	Update a course record
DELETE	/api/courses/{id}	Delete a course record
GET	/api/courses/cgpa	Calculate overall CGPA
GET	/api/courses/cgpa/semester/{semester}	Calculate semester GPA

API Usage Examples

Create a Course Record

curl -X POST http://localhost:8080/api/courses \
  -H "Content-Type: application/json" \
  -d '{
    "semester": "Fall 2024",
    "courseName": "Data Structures",
    "unit": 3,
    "grade": "A"
  }'

Request Body:

{
  "semester": "Fall 2024",
  "courseName": "Data Structures",
  "unit": 3,
  "grade": "A"
}

Response:

{
  "id": 1,
  "semester": "Fall 2024",
  "courseName": "Data Structures",
  "unit": 3,
  "grade": "A",
  "gradePoint": 5
}

Get All Course Records

curl http://localhost:8080/api/courses

Response:

[
  {
    "id": 1,
    "semester": "Fall 2024",
    "courseName": "Data Structures",
    "unit": 3,
    "grade": "A",
    "gradePoint": 5
  },
  {
    "id": 2,
    "semester": "Fall 2024",
    "courseName": "Algorithms",
    "unit": 4,
    "grade": "B",
    "gradePoint": 4
  }
]

Calculate Overall CGPA

curl http://localhost:8080/api/courses/cgpa

Response:

{
  "cgpa": 4.43,
  "totalUnits": 7,
  "totalGradePoints": 31,
  "semester": null
}

Calculate Semester GPA

curl http://localhost:8080/api/courses/cgpa/semester/Fall%202024

Response:

{
  "cgpa": 4.43,
  "totalUnits": 7,
  "totalGradePoints": 31,
  "semester": "Fall 2024"
}

Get Courses by Semester

curl http://localhost:8080/api/courses/semester/Fall%202024

Update a Course Record

curl -X PUT http://localhost:8080/api/courses/1 \
  -H "Content-Type: application/json" \
  -d '{
    "semester": "Fall 2024",
    "courseName": "Advanced Data Structures",
    "unit": 4,
    "grade": "A"
  }'

Delete a Course Record

curl -X DELETE http://localhost:8080/api/courses/1

Testing with Sample Data

Create multiple course records to test CGPA calculation:

# Course 1
curl -X POST http://localhost:8080/api/courses \
  -H "Content-Type: application/json" \
  -d '{"semester": "Fall 2024", "courseName": "Data Structures", "unit": 3, "grade": "A"}'

# Course 2
curl -X POST http://localhost:8080/api/courses \
  -H "Content-Type: application/json" \
  -d '{"semester": "Fall 2024", "courseName": "Algorithms", "unit": 4, "grade": "B"}'

# Course 3
curl -X POST http://localhost:8080/api/courses \
  -H "Content-Type: application/json" \
  -d '{"semester": "Spring 2025", "courseName": "Database Systems", "unit": 3, "grade": "A"}'

# Calculate overall CGPA
curl http://localhost:8080/api/courses/cgpa

Error Handling

The API includes validation for:

• Unit must be a positive number
• Course name is required
• Semester is required
• Grade must be one of: A, B, C, D, E, F

License

This project is open source and available under the MIT License.

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.