In C++, when do you use the :: scope resolution operator and what problem does it solve?

Introduction / Context:
The C plus plus scope resolution operator :: is a key part of the language syntax. It allows programmers to specify which scope a particular name belongs to, which is important in a language that supports namespaces, classes, and global variables. This question asks when you use the :: operator and what problem it is designed to solve in real C plus plus programs.

Given Data / Assumptions:

• C plus plus has multiple levels of scope, including global, namespace, class, and local scopes.
• Names such as variables, functions, and types can be declared at different levels.
• Sometimes names in inner scopes hide or shadow names in outer scopes.
• Programmers need a way to refer explicitly to the desired version of a name when ambiguities arise.

Concept / Approach:
The :: operator is used to qualify names with their enclosing scope. For example, you can write std::cout to access cout inside the std namespace, or ClassName::memberFunction to refer to a static member or to define a method outside the class body. Using :: with no left side, as in ::globalVar, refers specifically to a name in the global namespace, bypassing local or class members. In all of these cases, scope resolution clarifies which declaration the code should use when there might otherwise be confusion.

Step-by-Step Solution:
Step 1: Recognise that when two different declarations share the same name but reside in different scopes, the compiler needs help choosing the correct one.Step 2: Use ClassName::memberName to refer to a class static member or to specify that a method definition belongs to that class.Step 3: Use NamespaceName::functionName to call a function defined in a particular namespace, avoiding collisions with similarly named functions in other namespaces.Step 4: Use ::name to force access to a global variable or function when a local name shadows it.Step 5: Understand that in all these situations, the :: operator resolves the scope of the name, which is its primary purpose.

Verification / Alternative check:
Small code examples demonstrate the need for ::. If you define a global int value and a local int value inside main with the same name, value, then value refers to the local variable, while ::value refers to the global one. Similarly, if you define a function print inside two different namespaces, you must call them as ns1::print and ns2::print to avoid ambiguity. These examples show that scope resolution is essential for precise name binding in C plus plus.

Why Other Options Are Wrong:
Option B confuses the scope resolution operator with new or delete, which handle dynamic memory allocation and deallocation. Option C refers to equality comparison, typically implemented with the == operator or custom comparison functions. Option D mentions automatic numeric conversions, which are handled by implicit conversion rules or cast operators, not by ::. None of these behaviours involve resolving the scope of names, so they do not describe the purpose of the scope resolution operator.

Common Pitfalls:
A common pitfall is forgetting to qualify names from the std namespace, leading to compilation errors or unintended use of local identifiers. Another mistake is failing to understand the difference between static class members, which are accessed with ClassName::member, and instance members, which require an object. Overuse of global names can also create unnecessary reliance on ::. Designing clear namespaces and using scope resolution thoughtfully helps keep large C plus plus projects organised and maintainable.

Final Answer:
Correct answer: To qualify a name with its class, namespace, or global scope so that you can access the correct variable or function when there are naming conflicts