C# program to count the occurrences of each character in a String

Understanding the Problem:

Before we start writing code, it’s crucial to understand the problem at hand.

We want to create a C# program that takes a string as input and produces a count of each unique character in that string.

Table of Contents

1 Code Example 1: Program to find Character Occurrence in a String in C#
2 Code Example 2: Count occurrences of each character Using LINQ
3 Example 3: Using a Char Array
4 Related

Code Example 1: Program to find Character Occurrence in a String in C#

Let’s start with a simple approach using a dictionary to store character occurrences.

Below is the C# program to count the occurrences of each character in a String.

using System;
using System.Collections.Generic;

class CharacterCounter
{
    static void Main()
    {
        string inputString = "hello world";
        Dictionary<char, int> charCount = new Dictionary<char, int>();

        foreach (char c in inputString)
        {
            // Exclude spaces from character count
            if (c != ' ')
            {
                if (charCount.ContainsKey(c))
                    charCount++;
                else
                    charCount = 1;
            }
        }

        // Display the results
        foreach (var entry in charCount)
        {
            Console.WriteLine($"Character '{entry.Key}' occurs {entry.Value} times.");
        }
    }
}

Output:

Character 'h' occurs 1 times.
Character 'e' occurs 1 times.
Character 'l' occurs 3 times.
Character 'o' occurs 2 times.
Character 'w' occurs 1 times.
Character 'r' occurs 1 times.
Character 'd' occurs 1 times.

Code Explanation:

We use a Dictionary<char, int> to store characters and their corresponding counts.
The foreach loop iterates through each character in the input string.
We check if the character is already a key in the dictionary. If yes, we increment its count; otherwise, we add it with a count of 1.
Finally, we iterate through the dictionary to display the results.

Code Example 2: Count occurrences of each character Using LINQ

In the below code example, we will count each unique character in the string using LINQ (Language Integrated Query).

using System;
using System.Linq;

class CharacterCounter
{
    static void Main()
    {
        string inputString = "hello world";
        
        var charCount = inputString
            .Where(c => c != ' ') // Exclude spaces
            .GroupBy(c => c)
            .ToDictionary(g => g.Key, g => g.Count());

        // Display the results
        foreach (var entry in charCount)
        {
            Console.WriteLine($"Character '{entry.Key}' occurs {entry.Value} times.");
        }
    }
}

Code Explanation:

We use LINQ’s GroupBy to group characters and then ToDictionary to create our character count dictionary.
This approach is more concise and often preferred by most of the developers.

Example 3: Using a Char Array

We will use a character array to iterate through the string and update the character count.

In the below code example, we will find the Character Occurrence in a String in C#.

using System;

class CharacterCounter
{
    static void Main()
    {
        string inputString = "Hello World";
        // Remove empty spaces from the string
        inputString = inputString.Replace(" ", string.Empty);
        int[] charCount = new int[256]; // Assuming ASCII characters

        foreach (char c in inputString)
        {
            charCount++;
        }

        // Display the results
        for (int i = 0; i < 256; i++)
        {
            if (charCount[i] > 0)
            {
                Console.WriteLine($"Character '{(char)i}' occurs {charCount[i]} times.");
            }
        }
    }
}

Output:

Character 'H' occurs 1 times.
Character 'W' occurs 1 times.
Character 'd' occurs 1 times.
Character 'e' occurs 1 times.
Character 'l' occurs 3 times.
Character 'o' occurs 2 times.
Character 'r' occurs 1 times.

Code Explanation:

We use an integer array of size 256 to represent ASCII characters.
The array is initialized to zeros.
We iterate through the input string, and for each character, we increment the corresponding index in the array.
Finally, we iterate through the array to display non-zero counts.

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Shekh Ali

Meet Sheikh Ali, a skilled Software engineer and passionate a blogger. He enjoys sharing his expertise in C#, Java, SQL, Design Patterns, and other related topics through his writing. When he's not coding, Sheikh Ali can often indulge in his passions for reading books and fitness training.

Code Example 1: Program to find Character Occurrence in a String in C#

Code Example 2: Count occurrences of each character Using LINQ

Example 3: Using a Char Array

Related