# Basic Function Definition
# -------------------------
# A simple function that adds two numbers
add_numbers <- function(x, y) {
  sum <- x + y
  return(sum)
}

# Using the function
result <- add_numbers(5, 3)
print(paste("Sum:", result))

# Function with Default Parameters
# --------------------------------
# A function with default values for parameters
multiply_numbers <- function(x, y = 2) {
  product <- x * y
  return(product)
}

# Using the function with default parameter
default_product <- multiply_numbers(4)
print(paste("Default Product:", default_product))

# Using the function by specifying both parameters
specified_product <- multiply_numbers(4, 3)
print(paste("Specified Product:", specified_product))

# Returning Multiple Values
# -------------------------
# A function that returns multiple values using a list
operate_numbers <- function(a, b) {
  sum <- a + b
  diff <- a - b
  prod <- a * b
  return(list(sum = sum, difference = diff, product = prod))
}

# Using the function
results <- operate_numbers(10, 5)
print("Operations Result:")
print(results)

# Variable Scope
# --------------
# A function to demonstrate variable scope
outer_function <- function() {
  internal_var <- 20
  inner_function <- function() {
    print(paste("Accessing internal_var inside inner_function:", internal_var))
  }
  inner_function()
  return(internal_var)
}

# Using the function
outer_result <- outer_function()
print(paste("Returned from outer_function:", outer_result))

# Anonymous Functions
# -------------------
# Using an anonymous function (a function without a name)
squared_numbers <- sapply(1:5, function(x) x^2)
print("Squared Numbers:")
print(squared_numbers)