Explain each of the following operators and how and when they should be used: ==, ===, eql?, equal?.

[geekelo]

Mock Technical Interview: Operator Explanation

Objective:

The goal of this technical interview question is to assess the candidate's understanding of different comparison operators in programming, specifically in languages like JavaScript and Ruby.

Operators:

1. == Operator:

   • Explanation: This is the equality operator that checks if the values on both sides are equal after type coercion.
   • Use Case: It is commonly used for loose equality checks when you want to compare values but don't necessarily care about their types being the same.

2. === Operator:

   • Explanation: This is the strict equality operator that checks if both the value and the type are the same.
   • Use Case: It is used for strict equality checks, ensuring that not only the values but also the types match.

3. eql? Method:

   • Explanation: In Ruby, eql? is a method used for hash key comparison, but its behavior depends on the class.
   • Use Case: It is often used when dealing with custom objects in Ruby where you want to compare objects based on their content.

4. equal? Method:

   • Explanation: In Ruby, equal? checks if both operands refer to exactly the same object in memory.
   • Use Case: It is used when you want to verify if two variables reference the exact same object instance.

Guidance for the Candidate:

• == vs. ===: Emphasize the importance of type consideration in strict equality checks (===) compared to loose equality checks (==).
• eql? vs. equal?: Explain the context in which these Ruby-specific methods are employed, highlighting scenarios involving custom objects and memory references.

Additional Notes:

• Encourage candidates to provide examples in multiple programming languages to demonstrate versatility.
• Evaluate not only correctness but also the candidate's ability to communicate technical concepts clearly.