What Does the \'override\' Keyword Do in C and Why Is It Important?

Exploring the 'override' Keyword in C

While navigating the intricacies of C as a beginner, you may have stumbled upon the mysterious 'override' keyword. This enigmatic term holds a significant purpose in the world of virtual functions and class inheritance.

Unveiling the Role of 'override'

The 'override' keyword serves a dual mission:

1. Communicating Intent: It clearly indicates to the code reader that the marked method overrides a virtual method defined in the base class.
2. Compiler Verification: The compiler can leverage this keyword to verify that any changes made to an overriden method adhere to specific rules. It ensures that new or modified methods maintain the contract established by the base class.

An Illustrative Example

To solidify our understanding, let's delve into a practical example:

<code class="cpp">class Base {
public:
  virtual int foo(float x) = 0;
};

class Derived : public Base {
public:
  int foo(float x) override { ... }  // Valid override
};

class Derived2 : public Base {
public:
  int foo(int x) override { ... }  // Invalid override (type change)
};</code>

In Derived, the 'override' keyword serves as a safety net, ensuring that the implementation of foo matches the signature specified in the base class. On the other hand, the override in Derived2 triggers a compiler error because the new method alters the method signature.

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