C#: Check if a given string contains two similar consecutive letters

C# Sharp Basic: Exercise-71 with Solution

Check Consecutive Similar Letters

Write a C# Sharp program to check if a given string contains two similar consecutive letters.

Sample Solution:

C# Sharp Code:

using System;

namespace exercises
{
    class Program
    {
        // Main method where the program execution begins
        static void Main(string[] args)
        {
            // Displays original strings and tests for consecutive similar letters
            Console.WriteLine("Original string: PHP");
            Console.WriteLine("Test for consecutive similar letters! " + test("PHP"));

            Console.WriteLine("Original string: PHHP");
            Console.WriteLine("Test for consecutive similar letters! " + test("PHHP"));

            Console.WriteLine("Original string: PHPP");
            Console.WriteLine("Test for consecutive similar letters! " + test("PHPP"));

            Console.WriteLine("Original string: PPHP");
            Console.WriteLine("Test for consecutive similar letters! " + test("PPHP"));
        }

        // Function to test if a string contains consecutive similar letters
        public static bool test(string text)
        {
            // Iterates through the characters of the string except the last character
            for (int i = 0; i < text.Length - 1; i++)
            {
                // Checks if the current character is the same as the next character
                // If consecutive similar letters are found, returns true
                if (text[i] == text[i + 1]) 
                { 
                    return true; 
                }
            }

            // Returns false if no consecutive similar letters are found in the string
            return false;
        }
    }
}

Sample Output:

Original string: PHP
Test for consecutive similar letters! False
Original string: PHHP
Test for consecutive similar letters! True
Original string: PHPP
Test for consecutive similar letters! True
Original string: PPHP
Test for consecutive similar letters! True

Flowchart:

Sample Solution-1:

C# Sharp Code:

using System;
using System.Text.RegularExpressions;

namespace exercises
{
    class Program
    {
        // Main method where the program execution begins
        static void Main(string[] args)
        {
            // Displays original strings and tests for consecutive similar letters
            Console.WriteLine("Original string: PHP");
            Console.WriteLine("Test for consecutive similar letters! " + test("PHP"));

            Console.WriteLine("Original string: PHHP");
            Console.WriteLine("Test for consecutive similar letters! " + test("PHHP"));

            Console.WriteLine("Original string: PHPP");
            Console.WriteLine("Test for consecutive similar letters! " + test("PHPP"));

            Console.WriteLine("Original string: PPHP");
            Console.WriteLine("Test for consecutive similar letters! " + test("PPHP"));
        }

        // Function to test if a string contains consecutive similar letters
        public static bool test(string text)
        {
            // Uses Regex.IsMatch to check if the input string matches a pattern
            // The pattern (.)\1 matches any character (captured by the group (.) represented by \1) that repeats consecutively
            // If a match is found, it returns true, indicating consecutive similar letters
            return Regex.IsMatch(text, @"(.)\1");
        }
    }
}

Sample Output:

Original string: PHP
Test for consecutive similar letters! False
Original string: PHHP
Test for consecutive similar letters! True
Original string: PHPP
Test for consecutive similar letters! True
Original string: PPHP
Test for consecutive similar letters! True

Flowchart:

C# Sharp Code Editor:

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