String calculator

We use this kata to develop the fundamentals of classic TDD.

Overview

In the string calculator kata, you write a method which calculates the sum of the numbers passed to it. However, the method takes only one parameter, which is a string. You must therefore parse and convert the string before being able to perform the calculation.

Objectives

Write a program which exposes a method with the following signature:

int Add(string bowlingGameScores)

The must remain the same as you work through the following objectives:

Parse the input and return the correct sum of the numbers

• If the input is empty, return 0.

• If the input contains a single number, return that number.

• If the input contains two numbers separated by a comma, return the sum of the two numbers, e.g. "1,2" returns 3.

  • The comma delimiter cannot appear at the beginning or the end of the line, e.g. ",1,2" or "1,2,"

  • The comma delimiter cannot appear more than once in a row, e.g. "1,,2"

Handle an unknown amount of numbers

• e.g. "1,2,3,4,5,6,...n"

Handle newline as well as commas between numbers

• Numbers can be delimited by a comma, e.g. "1,2,3"

• Numbers can be delimited by a newline, e.g. "1\n2\n3"

• Numbers can be delimited by either a comma or a newline, e.g. “1\n2,3”

• Delimiters cannot appear more than one in a row, e.g. 1\n,2

Support custom delimiters

• To set the delimiter, the beginning of the string should contain a separate line using this format: “//[delimiter]\n[numbers]” e.g. “//*\n1*2”

• Delimiters can be of any length, e.g. “//***\n1***2***3”

• The first line is optional, so all existing scenarios must still be supported.

Throw an exception when passed a negative number

• Passing a negative number will throw an exception with the message “Sorry, I'm not feeling very positive about this input: -n” where n is the negative number passed int.

• If there are multiple negative numbers, show all of them in the exception message.

Numbers greater than 1000 are reset to 0

• e.g. "2,1001" returns 3

• e.g. "2,999" returns 1

Support multiple custom delimiters

• Custom delimiters can be delimited using this format: “//[delimiter1]/[delimiter2]\n[numbers]” e.g. “//*/%\n1*2%3”