A professional Java desktop application that evaluates mathematical expressions. It utilizes the Stack data structure to convert Infix notation into Postfix (Reverse Polish Notation) and computes the final result.
The application correctly handles parentheses and multiple operators, showing the step-by-step conversion.
Demonstrating the system's ability to prioritize operations like multiplication and division over addition.
This project is a practical implementation of two major Stack algorithms:
- Shunting-Yard Algorithm: To convert standard expressions (Infix) into a machine-readable format (Postfix).
- Postfix Evaluation: Using a second stack to calculate the result from the converted expression.
- User Input:
100 / (2 * 5) + 15 - Internal Postfix:
100 2 5 * / 15 + - Computed Result:
25.0
graph TD
A[Input Expression] --> B{Is it an Operand?}
B -- Yes --> C[Add to Output/Postfix]
B -- No --> D{Is it an Operator?}
D -- "(" --> E[Push to Stack]
D -- ")" --> F["Pop till '('"]
D -- "+, -, *, /" --> G{Check Precedence}
G -- Higher --> H[Push to Stack]
G -- Lower/Equal --> I[Pop Stack to Output & Push New]
C --> J[End of Expression?]
F --> J
H --> J
I --> J
J -- Yes --> K[Pop Remaining Stack to Output]
K --> L[Final Postfix Result]
- Modern Dark UI: Clean aesthetic for a professional look.
- Error Validation: Detects and reports invalid mathematical expressions.
- Multi-digit Support: Efficiently parses numbers with multiple digits and decimals.
- Real-time Feedback: Shows both the postfix string and the result instantly.
- Language: Java
- UI Framework: Java Swing / AWT (GUI)
- Data Structure: Stack (Last-In-First-Out logic)
- Clone the Repo:
git clone [https://github.com/bushra-waseem/Java-Expression-Evaluator-GUI.git](https://github.com/bushra-waseem/Java-Expression-Evaluator-GUI.git)
- Open in IDE: Import the project into IntelliJ IDEA, Eclipse, or NetBeans.
- Compile & Run: Run the main Java file to launch the GUI window.
- LinkedIn: [Bushra Waseem](https://www.linkedin.com/in/ bushraa-waseem)