Summary of C# Strings

Introduction to Strings

• Definition: Strings are sequences of characters used to represent text in C#.
• Data Type: In C#, a string is an object of the System.String class.

Creating Strings

• Strings can be created using:
  • Double quotes: string greeting = "Hello, World!";
  • String interpolation: string name = "Alice"; string message = $"Hello, {name}!";

Key Concepts

• Immutable: Strings in C# are immutable, meaning once created, their value cannot be changed.
• Concatenation: You can combine strings using the + operator or String.Concat method.
  • Example: string fullName = firstName + " " + lastName;

String Methods

• C# provides various built-in methods for string manipulation:
  • Length: int length = myString.Length;
  • Substring: Extracts a part of the string. Example: string sub = myString.Substring(0, 5);
  • ToUpper() / ToLower(): Converts the string to upper or lower case.
    • Example: string upper = myString.ToUpper();
  • IndexOf(): Finds the position of a character or substring.
    • Example: int index = myString.IndexOf("World");
  • Replace(): Replaces occurrences of a specified string.
    • Example: string newStr = myString.Replace("World", "C#");

String Formatting

• Strings can be formatted using:
  • String Format: string formatted = String.Format("Hello, {0} !", name);
  • Interpolation: As shown in the creation example above.

Escape Sequences

• Special characters in strings can be represented using escape sequences, such as:
  • \n for new line
  • \t for tab
  • \\ for backslash

Conclusion

• Strings are a fundamental part of C# programming, and understanding how to manipulate them is crucial for effective coding.

Example Code

string firstName = "John";
string lastName = "Doe";
string fullName = firstName + " " + lastName;
Console.WriteLine(fullName); // Output: John Doe

This summary provides a fundamental overview of strings in C#, designed for beginners to grasp the essential concepts and usage.