Send for calling methods dynamically in Ruby - Mini Project: Build & Apply

Send for calling methods dynamically

📖 Scenario: Imagine you have a simple calculator that can perform different operations like addition, subtraction, multiplication, and division. You want to call these operations dynamically based on user input.

🎯 Goal: Build a Ruby program that uses send to call calculator methods dynamically.

📋 What You'll Learn

Create a class Calculator with methods add, subtract, multiply, and divide

Create an instance of Calculator called calc

Create a variable operation that stores the method name as a symbol

Use send on calc with operation and two numbers to get the result

Print the result

💡 Why This Matters

🌍 Real World

Dynamic method calling is useful when you want to choose actions at runtime, like in calculators, menus, or command handlers.

💼 Career

Understanding <code>send</code> helps in metaprogramming and building flexible Ruby applications that adapt to different inputs or commands.

1

Create the Calculator class with methods

Create a class called Calculator with four methods: add, subtract, multiply, and divide. Each method takes two parameters a and b and returns the result of the operation.

Ruby

# Define class Calculator with methods add, subtract, multiply, divide
# Your code here

Need a hint?

Define each method inside the class with two parameters and return the calculation.

2

Create an instance and set operation variable

Create an instance of Calculator called calc. Then create a variable called operation and set it to the symbol :multiply.

Ruby

class Calculator
  def add(a, b)
    a + b
  end

  def subtract(a, b)
    a - b
  end

  def multiply(a, b)
    a * b
  end

  def divide(a, b)
    a / b
  end
end

# Create instance calc and set operation to :multiply
# Your code here

Need a hint?

Use Calculator.new to create the instance and assign :multiply to operation.

3

Use send to call the method dynamically

Use send on the calc object with the operation variable and the numbers 6 and 7 as arguments. Store the result in a variable called result.

Ruby

class Calculator
  def add(a, b)
    a + b
  end

  def subtract(a, b)
    a - b
  end

  def multiply(a, b)
    a * b
  end

  def divide(a, b)
    a / b
  end
end

calc = Calculator.new
operation = :multiply

# Use send to call the method dynamically with 6 and 7
# Your code here

Need a hint?

Use calc.send(operation, 6, 7) to call the method stored in operation.

4

Print the result

Print the value of the variable result.

Ruby

class Calculator
  def add(a, b)
    a + b
  end

  def subtract(a, b)
    a - b
  end

  def multiply(a, b)
    a * b
  end

  def divide(a, b)
    a / b
  end
end

calc = Calculator.new
operation = :multiply
result = calc.send(operation, 6, 7)

# Print the result
# Your code here

Need a hint?

Use puts result to display the output.