C# Strings Lecture Notes

Introduction to Strings

• Strings are sequences of characters.
• Defined in C# using double quotes, e.g., "Hello World".
• Each character (like 'A', 'B', 'C') is an individual unit in a string.

String Declaration

• Example: string firstFriend = "Maria";
  • string: Data type.
  • firstFriend: Variable name.
  • Maria: Value stored in the variable.
  • ;: Semicolon denotes the end of the statement (similar to a period in a sentence).

Variable Naming

• Variables can be named anything (e.g., firstFriend, f).
• The choice of name should be meaningful.

Console Output

• Using Console.WriteLine to output strings.
• Example: Console.WriteLine($"My friends are {firstFriend} and {secondFriend}");
  • $: Indicates string interpolation.
  • Curly braces {} are used to embed variable values within strings.

String Interpolation vs. Concatenation

• String Interpolation: Easier to read and write, substitutes variable values directly.
• Concatenation: Joining strings using + operator.
  • Example: "My friends are " + firstFriend + " and " + secondFriend;
• Both methods achieve the same goal but interpolation is preferred for readability.

Error Handling in C# Strings

• C# is a strongly typed language, providing compile-time error checking.
• Errors highlighted immediately (red squiggles for errors, yellow for warnings) in the IDE.

Trimming Strings

• Trimming removes whitespace from the start and end of strings.
• Example: firstFriend = firstFriend.Trim();
• Whitespace outside of quotes does not affect the string.
• Both leading and trailing spaces can be removed using .Trim() method.

Intellisense in C#

• Provides code completion and helps in writing code efficiently by suggesting methods and properties as you type.

Practical Example of Trimming

• To trim strings in C#:
  • string firstFriend = " Maria "; (with spaces).
  • firstFriend = firstFriend.Trim(); to remove spaces.
• Check results using Console.WriteLine() after trimming.

Conclusion

• C# strings are powerful and flexible.
• String manipulation techniques like interpolation and trimming are essential for effective coding.