Triangle Calculator Demo

Overview

This project is a demonstration of how to handle user input in Java and use object-oriented programming (OOP) concepts such as inheritance and polymorphism. The program allows users to select a type of triangle, provide relevant inputs, and calculate properties such as area and perimeter.

How User Input Works

1. Scanner Class: The program uses the Scanner class to read user input from the console.
2. Input Prompts: The user is prompted to enter specific values (e.g., side lengths, angles) based on the type of triangle they select.
3. Validation: The program assumes valid input for simplicity. In a real-world application, additional validation would be required to handle invalid or unexpected input.

Example of User Input

• The user is asked to select a triangle type by entering a number (e.g., 1 for Equilateral Triangle).
• Based on the selection, the program prompts the user for specific inputs, such as:
  • Side lengths for an equilateral triangle.
  • Two sides and an angle for an SSA triangle.
  • One side and two angles for an AAS triangle.

Classes and Their Responsibilities

Triangle (Abstract Class)

• Purpose: Serves as the base class for all triangle types.
• Fields:
  • sides: An array to store the lengths of the triangle's sides.
  • angles: An array to store the triangle's angles in degrees.
  • area: Stores the calculated area of the triangle.
  • perimeter: Stores the calculated perimeter of the triangle.
• Methods:
  • getInputAndCalculate(): Abstract method implemented by subclasses to handle input and calculations.
  • toString(): Formats the triangle's properties (sides, angles, area, and perimeter) for display.

EquilateralTriangle

• Purpose: Represents an equilateral triangle where all sides and angles are equal.
• Input: The user provides the length of one side.
• Calculations:
  • Area is calculated using the formula:
    [ \text{Area} = \frac{\sqrt{3}}{4} \times \text{side}^2 ]
  • Perimeter is calculated as:
    [ \text{Perimeter} = 3 \times \text{side} ]

SSATriangle

• Purpose: Represents a triangle defined by two sides and the angle between them.
• Input: The user provides two side lengths and the angle (in degrees) between them.
• Calculations:
  • Area is calculated using the formula:
    [ \text{Area} = 0.5 \times a \times b \times \sin(\text{angle}) ]
  • Perimeter is partially calculated (third side is not determined in this demo).

AASTriangle

• Purpose: Represents a triangle defined by one side and two angles.
• Input: The user provides one side length and two angles (in degrees).
• Calculations:
  • The third angle is calculated as:
    [ \text{Angle}_3 = 180 - (\text{Angle}_1 + \text{Angle}_2) ]
  • Area is calculated using the formula:
    [ \text{Area} = \frac{\text{side}^2 \times \sin(\text{Angle}_1) \times \sin(\text{Angle}_2)}{2 \times \sin(\text{Angle}_3)} ]
  • Perimeter is partially calculated (other sides are not determined in this demo).

TriangleSelector

• Purpose: Manages the user interaction and triangle selection process.
• Responsibilities:
  • Displays a menu for the user to select a triangle type.
  • Creates an instance of the selected triangle type.
  • Calls the getInputAndCalculate() method of the selected triangle to handle input and calculations.

How to Run the Program

1. Compile the project using Maven or your preferred IDE.
2. Run the Main class.
3. Follow the prompts to:
   • Select a triangle type.
   • Enter the required inputs.
4. View the calculated properties of the triangle (sides, angles, area, and perimeter).

Key Learning Points

• User Input: Using the Scanner class to read and process user input.
• OOP Concepts: Demonstrating inheritance, polymorphism, and abstraction.
• Mathematical Calculations: Applying trigonometric functions to calculate triangle properties.

This demo is designed to help students understand how to structure programs using OOP principles and handle user input effectively in Java.