The "Calculator" project aims to develop a simple, user-friendly calculator that performs basic arithmetic operations such as addition, subtraction, multiplication, and division. The calculator should support advanced operations like percentages, square roots, and memory functions. The application will be built to handle both integer and decimal calculations, providing accurate results with a clean, easy-to-use interface.

### Detailed Description

Calculators are essential tools for solving mathematical problems quickly and efficiently. This project will create a calculator application that performs a wide range of arithmetic operations, from basic to advanced. Here’s a detailed look at how users will interact with the app:

**Basic Arithmetic Operations**:**Addition**: The calculator will allow users to add two or more numbers.**Subtraction**: Users can subtract one number from another.**Multiplication**: Users can multiply numbers together.**Division**: Users can divide one number by another, with appropriate handling for division by zero.

**Advanced Operations**:**Percentage Calculation**: The calculator will allow users to find percentages of numbers.**Square Root Calculation**: Users can calculate the square root of a number.**Power and Exponents**: The calculator will support raising a number to a power or calculating exponents.

**Memory Functions**:**Memory Add (M+)**: Users can add a number to memory.**Memory Subtract (M-)**: Users can subtract a number from memory.**Memory Recall (MR)**: Users can recall the last number stored in memory.**Memory Clear (MC)**: Users can clear the stored memory.

**Decimal Support**:**Decimal Precision**: The calculator will support decimal numbers, allowing users to perform operations with high precision.

**User Interface**:**Clean Layout**: The calculator will have a clean, intuitive user interface, displaying buttons for each arithmetic operation and number input.**Result Display**: The app will display the result of the calculation in a clear, easy-to-read format.

**Error Handling**:**Division by Zero**: The app will handle division by zero, displaying an error message or an appropriate response like "undefined."**Input Validation**: The calculator will validate user input to ensure only valid operations and numbers are processed.

### Real-World Example

Imagine a user, John, who needs to calculate his monthly expenses. John opens the calculator and starts by adding his rent, utilities, and grocery costs. After performing a few basic calculations, he uses the percentage function to calculate how much of his budget goes toward rent. John also uses the memory functions to store intermediate results while performing more complex calculations involving taxes and savings.

## Table of Contents

## 1. Introduction

The "Calculator" project aims to develop a basic and advanced calculator that supports a wide range of arithmetic operations. The app will allow users to perform simple mathematical calculations, as well as more complex operations like percentages and square roots.

## 2. Objectives

Enable users to perform basic arithmetic operations (addition, subtraction, multiplication, division).

Support advanced operations like percentages, square roots, and powers.

Provide memory functions for adding, subtracting, recalling, and clearing stored values.

Handle both integer and decimal calculations with precision.

Deliver a clean, user-friendly interface that ensures easy use and accurate results.

## 3. Functional Requirements

### Basic Arithmetic

**Addition**: Users can add two or more numbers.**Subtraction**: Users can subtract numbers.**Multiplication**: Users can multiply numbers.**Division**: Users can divide numbers, with error handling for division by zero.

### Advanced Operations

**Percentage Calculation**: Users can calculate percentages.**Square Root**: Users can calculate the square root of a number.**Power/Exponents**: Users can raise a number to a power.

### Memory Functions

**M+ (Memory Add)**: Add the current result to memory.**M- (Memory Subtract)**: Subtract the current result from memory.**MR (Memory Recall)**: Recall the value stored in memory.**MC (Memory Clear)**: Clear the stored memory.

### Decimal Support

**Precision Calculation**: Support calculations with decimal numbers and high precision.

### User Interface

**Display**: Show the current input, operation, and result in a clear display.**Buttons**: Provide buttons for numbers, arithmetic operations, and memory functions.

### Error Handling

**Division by Zero**: Handle division by zero gracefully.**Input Validation**: Ensure only valid numbers and operations are processed.

## 4. Non-Functional Requirements

**Scalability**: The calculator should handle a growing number of calculations without performance degradation.**Performance**: The app should process calculations quickly and return results in real-time.**Usability**: The user interface should be intuitive, making the calculator easy to use for all types of users.**Reliability**: The calculator should consistently return accurate results.

## 5. Use Cases

**Basic Calculations**: Users perform basic arithmetic operations such as addition and subtraction.**Advanced Calculations**: Users calculate percentages, square roots, and powers.**Memory Operations**: Users store intermediate values in memory to recall later.

## 6. User Stories

As a user, I want to perform basic arithmetic operations like addition, subtraction, multiplication, and division.

As a user, I want to calculate percentages to understand parts of a whole.

As a user, I want to calculate the square root of a number.

As a user, I want to store a value in memory and recall it later during a calculation.

As a user, I want to perform calculations with decimal numbers for higher precision.

As a user, I want the calculator to show an error if I try to divide by zero.

## 7. Technical Requirements

**Programming Language**: Choose an appropriate programming language (e.g., JavaScript for web-based, Python for a desktop app).**Decimal Support**: Implement accurate decimal handling for precise calculations.**Error Handling**: Ensure robust error handling for invalid operations (e.g., division by zero).**Interface**: Develop a user-friendly interface with responsive buttons and display.

## 8. API Endpoints (for online calculator services)

`POST /calculate`

: Send calculation data (operation, numbers) to perform a calculation and return the result.`GET /history`

: Retrieve the user's past calculations.

## 9. Security

**Input Validation**: Validate user input to prevent injection attacks in online versions.**Data Encryption**: Securely handle sensitive data (e.g., stored memory values) if necessary.

## 10. Performance

**Real-Time Calculation**: Ensure that calculations are processed and results displayed in real-time.**Optimized Algorithms**: Use optimized algorithms to handle large or complex calculations.

## 11. Documentation

Provide a user manual explaining how to perform basic and advanced operations.

Include developer documentation for maintaining the codebase and adding new features.

## 12. Glossary

**API**: Application Programming Interface.**CRUD**: Create, Read, Update, Delete (used in some calculator services).

## 13. Appendix

Include relevant diagrams, UI mockups, and additional resources.

Let me know if you need any further modifications or additional details!