#README

This project is an implementation of the String Calculator TDD in Rails 8 using ActiveRecord. The calculator follows a strict Test-Driven Development (TDD) approach, with incremental commits showcasing the evolution of the code.

Features

Adds numbers from a comma-separated string input.

Handles any number of integers.

Supports new line (\n) as a delimiter.

Supports custom delimiters using the format: //[delimiter]\n[numbers].

Raises an exception for negative numbers, listing all of them in the error message.

Installation

Clone the repository:

	git clone https://github.com/nidhi-soni1104/calculator-rails8
	cd string_calculator

Install dependencies:

  bundle install

Set up the database:

  rails db:migrate

Run tests:

  rspec

Usage

To use the calculator, call the .add method on the Calculator model:

Calculator.add("")        # => 0
Calculator.add("1")       # => 1
Calculator.add("1,5")     # => 6
Calculator.add("1,2,3,4") # => 10
Calculator.add("1\n2,3") # => 6
Calculator.add("//;\n1;2") # => 3
Calculator.add("-1,2,-3") # => Exception: "Negative numbers not allowed: -1, -3"

Test Cases:

✅ Returns 0 for an empty string.

✅ Returns the number itself for a single number.

✅ Returns the sum of two comma-separated numbers.

✅ Handles multiple numbers.

✅ Supports new lines as delimiters.

✅ Supports custom delimiters.

✅ Raises an exception for negative numbers.