Comparing two strings in C# and getting the differences only can be achieved by utilizing various string manipulation techniques and algorithms. In this article, we will explore different approaches to solve this problem and provide examples to illustrate the solutions.

## Approach 1: Using the SequenceEqual Method

The SequenceEqual method in C# can be used to compare two sequences, including strings. By converting the strings into character arrays, we can compare each character and identify the differences.

```
string str1 = "Hello";
string str2 = "Hella";
char[] charArray1 = str1.ToCharArray();
char[] charArray2 = str2.ToCharArray();
bool areEqual = charArray1.SequenceEqual(charArray2);
if (!areEqual)
{
string differences = "";
for (int i = 0; i < charArray1.Length; i++)
{
if (charArray1[i] != charArray2[i])
{
differences += charArray2[i];
}
}
Console.WriteLine("Differences: " + differences);
}
```

In this example, we compare the strings "Hello" and "Hella". The SequenceEqual method is used to check if the character arrays are equal. Since they are not equal, we iterate through each character and append the differing characters to the "differences" string. Finally, we print the differences, which in this case would be "a".

## Approach 2: Using the Except Method

The Except method in C# can be used to find the set difference between two sequences. By converting the strings into character arrays, we can find the characters that are present in one string but not in the other.

```
string str1 = "Hello";
string str2 = "Hella";
char[] charArray1 = str1.ToCharArray();
char[] charArray2 = str2.ToCharArray();
var differences = charArray2.Except(charArray1);
Console.WriteLine("Differences: " + string.Join("", differences));
```

In this example, we use the Except method to find the characters in "Hella" that are not present in "Hello". The resulting differences are then printed, which in this case would be "a".

## Approach 3: Using the Levenshtein Distance Algorithm

The Levenshtein Distance algorithm is a popular method for measuring the difference between two strings. It calculates the minimum number of single-character edits (insertions, deletions, or substitutions) required to change one string into another.

```
string str1 = "Hello";
string str2 = "Hella";
int[,] matrix = new int[str1.Length + 1, str2.Length + 1];
for (int i = 0; i <= str1.Length; i++)
{
matrix[i, 0] = i;
}
for (int j = 0; j <= str2.Length; j++)
{
matrix[0, j] = j;
}
for (int i = 1; i <= str1.Length; i++)
{
for (int j = 1; j <= str2.Length; j++)
{
int cost = (str1[i - 1] == str2[j - 1]) ? 0 : 1;
matrix[i, j] = Math.Min(Math.Min(matrix[i - 1, j] + 1, matrix[i, j - 1] + 1), matrix[i - 1, j - 1] + cost);
}
}
int differences = matrix[str1.Length, str2.Length];
Console.WriteLine("Differences: " + differences);
```

In this example, we calculate the Levenshtein Distance between the strings "Hello" and "Hella". The algorithm uses a matrix to store the minimum edit distances for each substring. The resulting differences, which represent the minimum number of edits required to transform one string into another, are then printed.

By utilizing these approaches and algorithms, you can compare two strings in C# and obtain the differences only. Whether you prefer using the SequenceEqual method, the Except method, or the Levenshtein Distance algorithm, these solutions provide different ways to tackle the problem based on your specific requirements.