C#: Check for repeated occurrences of words in a string

C# Sharp Regular Expression: Exercise-6 with Solution

Write a C# Sharp program to check for repeated occurrences of words in a given string.

Sample Data:
("C# C# syntax is highly expressive, yet it is is also simple and easy to to learn learn.") -> 3 matches found
("Red Green Green Black Black Green.") -> 2 matches found

Sample Solution:

C# Sharp Code:

using System;
using System.Text.RegularExpressions;

public class Test
{
    public static void Main()
    {
        // Define a regular expression for repeated words.
        Regex rx = new Regex(@"\b(?<word>\w+)\s+(\k<word>)\b",
          RegexOptions.Compiled | RegexOptions.IgnoreCase);

        // Define a test string.
        string text = "C# C# syntax is highly expressive, yet it is is also simple and easy to to learn learn.";
        //string text = "Red Green Green Black Black Green.";

        // Display the original string.
        Console.WriteLine("Original string: \n" + text);

        // Find matches.
        MatchCollection matches = rx.Matches(text);

        // Report the number of matches found.
        Console.WriteLine("{0} matches found in the said string:\n   ", matches.Count);

        // Report on each match.
        foreach (Match match in matches)
        {
            GroupCollection groups = match.Groups;
            Console.WriteLine("'{0}' repeated at positions {1} and {2}",
                              groups["word"].Value,
                              groups[0].Index,
                              groups[1].Index);
        }
    }
}

Sample Output:

Original string: 
C# C# syntax is highly expressive, yet it is is also simple and easy to to learn learn.
3 matches found in the said string:
   
'is' repeated at positions 42 and 45
'to' repeated at positions 69 and 72
'learn' repeated at positions 75 and 81

Flowchart:

C# Sharp Code Editor:

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