Question

(True/False) Only existing operators can be overloaded.

Short answer

True. Only existing operators can be overloaded.

Step-by-step solution

Understanding Operator Overloading

Operator overloading allows operators to have user-defined meanings on user-defined types (class types). However, overloading does not allow the creation of new operators nor can it change the precedence of operators. Therefore, only the operators that already exist in the language can be overloaded.

Evaluating the Statement

Since only existing operators can be overloaded, and no new operators can be introduced, the statement is true.

Key concepts

C++ User-Defined Types

C++ programming language enables developers to create their own data types, known as user-defined types. These types are particularly defined through classes or structs, which encapsulate data and functions together. User-defined types are integral to object-oriented programming, allowing for the creation of complex data models that reflect real-world problems.

For example, consider a Book data type. By defining a class Book in C++, programmers can store related attributes such as title, author, and ISBN in a single entity. Added to this, they can define methods, to perform operations specific to what a book might need, like read() or open(). This encapsulation and abstraction make code not only cleaner but also reusable and maintainable.

The design of these types paves the way for powerful features like operator overloading, where operators are given new meanings when applied to user-defined types.

Operator Overloading Rules

The practice of operator overloading in C++ is governed by a set of rules that ensures consistency and maintainability of code. Here are some key rules to keep in mind when overloading operators for user-defined types:

• Only existing operators can be overloaded; new operators cannot be created.
• Overloaded operators keep their original precedence and associativity.
• At least one operand must be a user-defined type to differentiate the overloaded operator from the built-in one.
• Some operators cannot be overloaded, for example, the scope (::), sizeof, and the member selector (.) operators.
• Assignment operator overloads should return a reference to the left-hand operand to allow for chain assignment.

These rules aim to preserve the intrinsic properties of operators while giving them greater utility with new, user-defined behaviors. By adhering to them, developers can extend the language's expressiveness without sacrificing its inherent logic and structure.

C++ Operators Precedence

In C++, operators precedence determines the order in which operators are evaluated in an expression. This is analogous to the precedence of arithmetic operations in mathematics, where multiplication is evaluated before addition.

For instance, in an expression like a + b * c, the multiplication is performed first, unless parentheses are used to override the precedence, as in (a + b) * c. It is vital to understand that operator overloading does not alter this established order. Therefore, when overloading operators for user-defined types, it's important to consider how the operators will be sequenced during evaluation to avoid unexpected behaviors.

Operator precedence is a fundamental concept that programmers must grasp to write correct and predictable expressions, especially when creating complex expressions involving overloaded operators in user-defined types.