Phone Number Analysis
Phone Number Analysis

Phone Number Analysis

Learning Exercise

While completing Phone Number Analysis, you'll learn 1 concept


This exercise has you analyze phone numbers.

You are asked to implement 2 features.

Phone numbers passed to the routines are guaranteed to be in the form NNN-NNN-NNNN e.g. 212-515-9876 and non-null.

1. Analyze a phone number

Your analysis should return 3 pieces of data

  1. An indication of whether the number has a New York dialing code ie. 212 as the first 3 digits
  2. An indication of whether the number is fake having 555 as a prefix code in positions 5 to 7 (numbering from 1)
  3. The last 4 digits of the number.

Implement the (static) method PhoneNumber.Analyze() to produce the phone number info.

// => (false, true, "1234")

2. Detect if a phone number has a fake prefix code (555)

Implement the (static) method PhoneNumber.IsFake() to detect whether the phone number is fake using the phone number info produced in task 1.

// => true
Last updated 1 February 2023
Edit via GitHub The link opens in a new window or tab
C# Exercism

Ready to start Phone Number Analysis?

Sign up to Exercism to learn and master C# with 62 concepts, 164 exercises, and real human mentoring, all for free.