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# gavronek's solution

## to Phone Number in the C# Track

Published at Jul 13 2018 · 0 comments
Instructions
Test suite
Solution

#### Note:

This solution was written on an old version of Exercism. The tests below might not correspond to the solution code, and the exercise may have changed since this code was written.

Clean up user-entered phone numbers so that they can be sent SMS messages.

The North American Numbering Plan (NANP) is a telephone numbering system used by many countries in North America like the United States, Canada or Bermuda. All NANP-countries share the same international country code: `1`.

NANP numbers are ten-digit numbers consisting of a three-digit Numbering Plan Area code, commonly known as area code, followed by a seven-digit local number. The first three digits of the local number represent the exchange code, followed by the unique four-digit number which is the subscriber number.

The format is usually represented as

``````(NXX)-NXX-XXXX
``````

where `N` is any digit from 2 through 9 and `X` is any digit from 0 through 9.

Your task is to clean up differently formatted telephone numbers by removing punctuation and the country code (1) if present.

For example, the inputs

• `+1 (613)-995-0253`
• `613-995-0253`
• `1 613 995 0253`
• `613.995.0253`

should all produce the output

`6139950253`

Note: As this exercise only deals with telephone numbers used in NANP-countries, only 1 is considered a valid country code.

## Source

Event Manager by JumpstartLab http://tutorials.jumpstartlab.com/projects/eventmanager.html

## Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

### PhoneNumberTest.cs

``````// This file was auto-generated based on version 1.4.0 of the canonical data.

using Xunit;
using System;

public class PhoneNumberTest
{
[Fact]
public void Cleans_the_number()
{
var phrase = "(223) 456-7890";
Assert.Equal("2234567890", PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Cleans_numbers_with_dots()
{
var phrase = "223.456.7890";
Assert.Equal("2234567890", PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Cleans_numbers_with_multiple_spaces()
{
var phrase = "223 456   7890   ";
Assert.Equal("2234567890", PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Invalid_when_9_digits()
{
var phrase = "123456789";
Assert.Throws<ArgumentException>(() => PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Invalid_when_11_digits_does_not_start_with_a_1()
{
var phrase = "22234567890";
Assert.Throws<ArgumentException>(() => PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Valid_when_11_digits_and_starting_with_1()
{
var phrase = "12234567890";
Assert.Equal("2234567890", PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Valid_when_11_digits_and_starting_with_1_even_with_punctuation()
{
var phrase = "+1 (223) 456-7890";
Assert.Equal("2234567890", PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Invalid_when_more_than_11_digits()
{
var phrase = "321234567890";
Assert.Throws<ArgumentException>(() => PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Invalid_with_letters()
{
var phrase = "123-abc-7890";
Assert.Throws<ArgumentException>(() => PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Invalid_with_punctuations()
{
var phrase = "123-@:!-7890";
Assert.Throws<ArgumentException>(() => PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Invalid_if_area_code_starts_with_0()
{
var phrase = "(023) 456-7890";
Assert.Throws<ArgumentException>(() => PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Invalid_if_area_code_starts_with_1()
{
var phrase = "(123) 456-7890";
Assert.Throws<ArgumentException>(() => PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Invalid_if_exchange_code_starts_with_0()
{
var phrase = "(223) 056-7890";
Assert.Throws<ArgumentException>(() => PhoneNumber.Clean(phrase));
}

[Fact(Skip = "Remove to run test")]
public void Invalid_if_exchange_code_starts_with_1()
{
var phrase = "(223) 156-7890";
Assert.Throws<ArgumentException>(() => PhoneNumber.Clean(phrase));
}
}``````
``````using System;
using System.Collections.Generic;
using System.Linq;

public class PhoneNumber
{
const string InvalidNumber = "0000000000";

public PhoneNumber(string dirtyNumber)
{
string digitOnlyNumber = string.Concat(dirtyNumber.Where(char.IsDigit));

Number = InvalidNumber;

if (digitOnlyNumber.Length == 10)
Number = digitOnlyNumber;

if (digitOnlyNumber.Length == 11 && digitOnlyNumber.StartsWith("1"))
Number = digitOnlyNumber.Remove(0, 1);

}

public string Number { get; set; }

public string AreaCode
{
get
{
return Number.Substring(0, 3);
}
}

public override string ToString()
{
string[] numberParts = SplitByPartSizes(Number, new[] {3, 3, 4}).ToArray();

return String.Format("({0}) {1}-{2}", numberParts[0], numberParts[1], numberParts[2]);
}

private IEnumerable<string> SplitByPartSizes(string stringToSplit, int[] partSizes)
{
string part = "";
int currentPart = 0;
int charsToPartEnd = partSizes[currentPart];

foreach (char c in stringToSplit)
{
part += c;
charsToPartEnd--;

if (charsToPartEnd == 0)
{
currentPart++;
if (currentPart < partSizes.Length)
charsToPartEnd = partSizes[currentPart];
yield return part;
part = "";
}
}
}
}``````