Lesson07-Arrays-Part4. Program class. namespace Lesson07ArraysPart4Prep { class Program { static double METER_TO_INCHES = 100 / 2.

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1 Lesson07-Arrays-Part4 Program class namespace Lesson07ArraysPart4Prep class Program static double METER_TO_INCHES = 100 / 2.54; static void Main(string[] args) Experiment01(); //Tuples Experiment02(); //Reviews Experiment03(); //Read disk file Experiment04(); //Merge arrays Experiment05(); //Common array elements Console.Read(); //Main private static void Experiment05() Console.WriteLine("\nExperiment05\n" + new string('-', 20)); //GOAL: Find common elements between two arrays (arrays have no duplicates) int[] a1 = 11, 33, 55 ; int[] a2 = 22, 33, 44, 66, 55, 88, 99 ; ShowArray("a1", a1); ShowArray("a2", a2); //phase1. find out how many common elements are there int totalcommons = 0; for (int i1 = 0; i1 < a1.length; i1++) int pos = Array.IndexOf(a2, a1[i1]); if (pos >= 0) totalcommons++; //phase2. copy common elements to new array a3[] int[] a3 = new int[totalcommons]; int i3 = 0; for (int i1 = 0; i1 < a1.length; i1++) int pos = Array.IndexOf(a2, a1[i1]); if (pos >= 0) a3[i3++] = a1[i1]; ShowArray("Common elements are...", a3); // Utility method-1. Shows a messasge and the contents of an INT array private static void ShowArray(string msg, int[] a) Console.WriteLine($"\nmsg"); for (int i = 0; i < a.length; i++)

2 Console.Write( $"a[i], "); Console.WriteLine("\n"); // Utility method-2. Shows a messasge and the contents of an STRING array private static void ShowArray(string msg, string[] a) Console.WriteLine($"\nmsg"); for (int i = 0; i < a.length; i++) Console.WriteLine($"i \t a[i]"); Console.WriteLine("\n"); private static void Experiment04() Console.WriteLine("\nExperiment04\n" + new string('-', 20)); //GOAL: Merge two sorted arrays int[] a1 = 11, 33, 55 ; int[] a2 = 22, 44, 66, 88, 99 ; //array a3[] will hold the data from a1[] and a2[] int[] a3 = new int[a1.length + a2.length]; int i1 = 0, i2 = 0, i3 = 0; //compare current elements from a1[] and a2[] while (i1 < a1.length && i2 < a2.length) if (a1[i1] < a2[i2]) a3[i3++] = a1[i1++]; else a3[i3++] = a2[i2++]; // one of the arrays has been totally moved to a3 // transfer the rest of the other array to destination a3[] while (i1 < a1.length) a3[i3++] = a1[i1++]; while (i2 < a2.length) a3[i3++] = a2[i2++]; //print results ShowArray("Merged data in a3[]", a3); private static void Experiment03() //GOAL: read a 'chunk' of text data. Break the text into words. //Locate given words in the text, sort words, etc. // /* * A long time ago, in a galaxy far, far away... * It is a period of civil war. Rebel * spaceships, striking from a hidden * base, have won their first victory * against the evil Galactic Empire. * During the battle, Rebel spies managed * to steal secret plans to the Empire s ultimate weapon,

3 * the DEATH STAR, an armored space station * with enough power to destroy an entire planet. * Pursued by the Empire s sinister agents, * Princess Leia races home aboard her starship, * custodian of the stolen plans that can save her people * and restore freedom to the galaxy... */ Console.WriteLine("\nExperiment03\n" + new string('-', 20)); string text = ""; try //try to read -at once- the disk file text = File.ReadAllText(@"c:/temp/StarWars.txt"); //echo on the screen the text read from disk Console.WriteLine(text); catch (Exception) //if there is a problem, report the error, then terminate with exit code Console.WriteLine(@"Error - need to put file StarWars.txt in the c:\temp\ folder"); System.Environment.Exit(111); //use the following characters to break the data text string[] separator = ",", ".", " ", "\n", "\r", "\t", "'" ; //split the text into words string[] token = text.split(separator, StringSplitOptions.RemoveEmptyEntries); ShowArray("Original token[] array", token); //sort array in ascending order Array.Sort(token); ShowArray("Sorted token[] array", token); //look for a key-word using the utility BinarySearch method string searchkey = "the"; int position = Array.BinarySearch(token, searchkey); Console.WriteLine($"searchKey is found at position"); //find the FIRST occurrence of the keyword (in case of duplicates) int left = position; while (position > 0 && token[left] == searchkey) left--; Console.WriteLine($"first searchkey is found at left"); private static void Experiment02() Console.WriteLine("\nExperiment02\n" + new string('-', 20)); //GOAL: design a support structure for a Customer's Review system //sample data is stored in an array of custom objects (Review class) Review[] list = new Review[] new Review(5, "Great!!!"), new Review(5, "Best Ever"), new Review(1, "Horrible"), new Review(3, "OK"), new Review(1, "The worst!"), new Review(5, "Excellent"), new Review(4, "Very good, believe me!") ; //show list contents

4 foreach (Review r in list) Console.WriteLine(r); //tally how many reviews are there for each star category int[] tally = new int[6]; //we ignore cell-sub-zero foreach(review r in list) tally[r.stars]++; double totalreviews = list.length; Console.WriteLine($"\nTotal reviews totalreviews:n0\n"); for (int i = 5; i > 0 ; i--) double pct = 100 * (tally[i] / totalreviews); Console.WriteLine($"Stars i Tally tally[i] " + $"Pct pct, 3:N0% Bars(tally[i])"); private static void Experiment01() Console.WriteLine("\nExperiment01\n" + new string('-', 20)); //SKIP - This is a new feature of C# 7.0 and it is called TUPLES. // observe how method returns TWO values at once. No need for out //or ref parameter passing //Convert a distance in meters for feet and Inches (English Distance) var ed = ConvertToEd(1.50); Console.WriteLine($"Feet ed.item1 Inches ed.item2"); //observe the return type is a TUPLE private static (int, int) ConvertToEd(double meters) int totalinches = (int)(meters * METER_TO_INCHES); int feet = totalinches / 12; int inches = totalinches % 12; return (feet, inches); private static string Bars(int width) //Utility for a simple bar chart return new string('x', width);

5 Review class namespace Lesson07ArraysPart4Prep class Review private int stars; private string comment; private DateTime revdate; public DateTime RevDate get return revdate; private set revdate = value; public string Comment get return comment; set comment = value; public int Stars get return stars; set stars = value; public Review(int starsvalue, string commentvalue) Stars = starsvalue; Comment = commentvalue; RevDate = DateTime.Now; public override string ToString() return string.format($"stars: Stars Date: RevDate Comment: Comment");

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