C#: Count Occurrences of a substring in a string

Last update on December 20 2024 12:44:26 (UTC/GMT +8 hours)

Write a C# Sharp program to count a specific string (case sensitive) in given text.

Sample Solution-1:

C# Sharp Code:

using System;
using System.Linq;

namespace exercises
{
    class Program
    {
        static void Main(string[] args)
        {
            // Declare and initialize string variables
            string text = "The quick brown fox jumps over the lazy dog.";
            string search_str = "The";

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

            // Display the occurrences of the search string in the original string
            Console.WriteLine("Occurrences of the said substring in the string: " + test(text, search_str));

            // Change the values of text and search_str
            text = "Red Green Black RedRed";
            search_str = "Red";

            // Display the new original string and search string
            Console.WriteLine("\nOriginal string and search string:\n" + text + " \n" + search_str);

            // Display the occurrences of the search string in the original string
            Console.WriteLine("Occurrences of the said substring in the string: " + test(text, search_str));

            // Change the values of text and search_str
            text = "Red Green Black";
            search_str = "Pink";

            // Display the new original string and search string
            Console.WriteLine("\nOriginal string and search string:\n" + text + " \n" + search_str);

            // Display the occurrences of the search string in the original string
            Console.WriteLine("Occurrences of the said substring in the string: " + test(text, search_str));
        }  

        // Define a method 'test' that takes two string arguments and returns an integer
        public static int test(string text, string search_str)
        {
            int count = 0;

            // Loop through the characters of the original string
            for (int i = 0; i < text.Length - search_str.Length + 1; i++)
            {
                // Check if the substring from the current position matches the search string
                if (text.Substring(i, search_str.Length) == search_str)
                {
                    count++; // Increment the count if a match is found
                }
            } 

            return count; // Return the total count of occurrences
        }
    }
}

Sample Output:

Original string and search string:
The quick brown fox jumps over the lazy dog. 
The
Occurrences of the said substring in the string: 1

Original string and search string:
Red Green Black RedRed 
Red
Occurrences of the said substring in the string: 3

Original string and search string:
Red Green Black 
Pink
Occurrences of the said substring in the string: 0

Flowchart :

Sample Solution-2:

C# Sharp Code:

using System;
using System.Linq;

namespace exercises
{
    class Program
    {
        static void Main(string[] args)
        {
            // Declare and initialize string variables
            string text = "The quick brown fox jumps over the lazy dog.";
            string search_str = "The";

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

            // Display the occurrences of the search string in the original string
            Console.WriteLine("Occurrences of the said substring in the string: " + test(text, search_str));

            // Change the values of text and search_str
            text = "Red Green Black RedRed";
            search_str = "Red";

            // Display the new original string and search string
            Console.WriteLine("\nOriginal string and search string:\n" + text + " \n" + search_str);

            // Display the occurrences of the search string in the original string
            Console.WriteLine("Occurrences of the said substring in the string: " + test(text, search_str));

            // Change the values of text and search_str
            text = "Red Green Black";
            search_str = "Pink";

            // Display the new original string and search string
            Console.WriteLine("\nOriginal string and search string:\n" + text + " \n" + search_str);

            // Display the occurrences of the search string in the original string
            Console.WriteLine("Occurrences of the said substring in the string: " + test(text, search_str));
        }  

        // Define a method 'test' that takes two string arguments and returns an integer
        public static int test(string text, string search_str)
        {
            // Calculate occurrences by finding the difference in lengths between the original string and a modified string
            // The modified string is created by removing all occurrences of the search string and dividing by its length
            return (text.Length - text.Replace(search_str, "").Length) / search_str.Length;
        }
    }
}

Sample Output:

Original string and search string:
The quick brown fox jumps over the lazy dog. 
The
Occurrences of the said substring in the string: 1

Original string and search string:
Red Green Black RedRed 
Red
Occurrences of the said substring in the string: 3

Original string and search string:
Red Green Black 
Pink
Occurrences of the said substring in the string: 0

Flowchart :

C# Sharp Code Editor:

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