**Course Title:** Ruby Programming: From Basics to Advanced Techniques **Section Title:** Control Structures and Functions **Topic:** Conditional statements: if, else, unless, case ### Overview of Conditional Statements Conditional statements are an essential part of programming languages, allowing you to make decisions and execute different blocks of code based on specific conditions. In Ruby, you'll learn four primary types of conditional statements: `if`, `else`, `unless`, and `case`. These statements help manage the flow of your program and make it more efficient. ### If Statements The `if` statement is the most basic conditional statement in Ruby. It checks for a condition, and if the condition is true, the code inside the block is executed. ```ruby x = 10 if x > 5 puts "x is greater than 5" end ``` In this example, the condition `x > 5` is evaluated as true, so the message "x is greater than 5" is printed. ### If-Else Statements The `if-else` statement provides an alternative block of code to be executed if the initial condition is not met. ```ruby x = 10 if x > 20 puts "x is greater than 20" else puts "x is less than or equal to 20" end ``` In this case, the condition `x > 20` is evaluated as false, so the message "x is less than or equal to 20" is printed. ### Unless Statements The `unless` statement is the opposite of `if`. It checks for a condition, and if the condition is false, the code inside the block is executed. ```ruby x = 10 unless x > 20 puts "x is less than or equal to 20" end ``` Here, the condition `x > 20` is evaluated as false, so the message "x is less than or equal to 20" is printed. ### Case Statements The `case` statement is similar to `if-else` statements but uses a more concise syntax for evaluating multiple conditions. ```ruby x = 10 case x when 5 puts "x is equal to 5" when 10 puts "x is equal to 10" when 15 puts "x is equal to 15" else puts "x is not 5, 10, or 15" end ``` In this example, the condition `x` is compared with the values specified in the `when` clauses. Since `x` is equal to 10, the message "x is equal to 10" is printed. #### Best Practices for Using Conditional Statements * Use `if` statements for simple conditions and `if-else` for more complex ones. * Use `unless` statements to make your code more readable when the condition is false. * Use `case` statements for evaluating multiple conditions. * Always keep the condition concise and clear. ### Summary and Key Takeaways * Conditional statements control the flow of a program's execution based on specific conditions. * `if` statements check a condition and execute a block of code if it's true. * `if-else` statements provide an alternative block of code to be executed if the condition is not met. * `unless` statements execute a block of code if the condition is false. * `case` statements evaluate multiple conditions and execute a block of code based on the match. ### Additional Resources * For more information on conditional statements in Ruby, visit the [Ruby Documentation on Conditional Expressions](https://ruby-doc.com/docs/ruby-doc-bundle/Manual/conditional_expressions.html). ### Comments and Questions If you have any questions or need help understanding conditional statements, feel free to leave a comment below. In the next topic, we'll cover 'Loops: while, until, for, each.' Stay tuned!