String in C#

To repeat a character in C#, you can use the new string(char c, int count) method. For example, to repeat the character '*' 10 times, you can use:

string repeatedChar = new string('*', 10);

To repeat a string in C#, you can use a for loop or the string.Concat method. For example, to repeat the string "hello" 3 times, you can use:

string originalString = "hello";
int repeatCount = 3;

// Using a for loop
string repeatedString = "";
for (int i = 0; i < repeatCount; i++)
{
    repeatedString += originalString;
}

// Using string.Concat
string repeatedString = string.Concat(Enumerable.Repeat(originalString, repeatCount));

To concatenate strings in C#, you can use the + operator, the string.Concat method, or the StringBuilder class. For example, to concatenate the strings "hello" and "world", you can use:

string str1 = "hello";
string str2 = "world";

// Using the + operator
string concatenatedString = str1 + " " + str2;

// Using string.Concat
string concatenatedString = string.Concat(str1, " ", str2);

// Using StringBuilder
StringBuilder sb = new StringBuilder();
sb.Append(str1);
sb.Append(" ");
sb.Append(str2);
string concatenatedString = sb.ToString();

To check if a string is a palindrome in C#, you can reverse the string and compare it to the original string. For example:

string str = "racecar";
string reversedStr = new string(str.Reverse().ToArray());

bool isPalindrome = str.Equals(reversedStr); // true

To convert a char[] to a string in C#, you can use the string constructor that takes a char[]. For example:

char[] charArray = { 'h', 'e', 'l', 'l', 'o' };
string str = new string(charArray); // "hello"

To read a string line by line in C#, you can use the StreamReader class. For example:

using (StreamReader reader = new StreamReader("file.txt"))
{
    string line;
    while ((line = reader.ReadLine()) != null)
    {
        Console.WriteLine(line);
    }
}

C# string concatenation:

string str1 = "Hello";
string str2 = " World";
string result = str1 + str2;
// Result: "Hello World"

Substring in C# string:

string original = "Hello World";
string substring = original.Substring(6, 5);
// Result: "World"

String interpolation in C#:

string name = "John";
int age = 30;
string message = $"My name is {name} and I am {age} years old.";
// Result: "My name is John and I am 30 years old."

C# string format examples:

string formatted = string.Format("Name: {0}, Age: {1}", "John", 30);
// Result: "Name: John, Age: 30"

Trimming whitespace in C# strings:

string withWhitespace = "   Hello   ";
string trimmed = withWhitespace.Trim();
// Result: "Hello"

C# string comparison methods:

string str1 = "apple";
string str2 = "orange";
int comparisonResult = string.Compare(str1, str2);
// Result: -1 (str1 comes before str2)

Parsing numbers from strings in C#:

string numberString = "123";
int parsedNumber = int.Parse(numberString);
// Result: 123

Replacing characters in C# strings:

string original = "Hello World";
string replaced = original.Replace("World", "Universe");
// Result: "Hello Universe"

Splitting strings in C#:

string names = "John,Jane,Jim";
string[] nameArray = names.Split(',');
// Result: ["John", "Jane", "Jim"]

Checking if a string contains a substring in C#:

string sentence = "The quick brown fox";
bool containsWord = sentence.Contains("fox");
// Result: true

Converting strings to uppercase or lowercase in C#:

string original = "Hello";
string upper = original.ToUpper();
string lower = original.ToLower();
// Result: upper="HELLO", lower="hello"

Regular expressions with strings in C#:

using System.Text.RegularExpressions;

string pattern = @"\d+";
string input = "123 abc";
Match match = Regex.Match(input, pattern);
// Result: match.Value="123"

C# string length and size:

string text = "Hello";
int length = text.Length;
// Result: length=5

Joining strings in C# with StringBuilder:

StringBuilder builder = new StringBuilder();
builder.Append("Hello");
builder.Append(" World");
string result = builder.ToString();
// Result: "Hello World"

Encoding and decoding strings in C#:

string original = "Hello World";
byte[] encodedBytes = Encoding.UTF8.GetBytes(original);
string decodedString = Encoding.UTF8.GetString(encodedBytes);
// Result: decodedString="Hello World"

C# verbatim string literals:

string path = @"C:\Users\John\Documents";
// No need to escape backslashes in verbatim string literals