What is the Purpose of the `override` Keyword in C ?

Understanding the 'override' Keyword in C

In the context of object-oriented programming, the 'override' keyword plays a significant role in defining the behavior of derived classes.

Functions of the 'override' Keyword:

1. Explicitly Indicate a Method Override:
   The 'override' keyword is used to denote that a method in a derived class overrides a virtual method in the base class. It serves as a clear indication for developers and the compiler that the derived method intends to override the base method.
2. Enforcement of Method Signature Matching:
   The compiler utilizes the 'override' keyword to verify that the method signature in the derived class matches the signature of the virtual method in the base class. This prevents unintentional alterations or additions to the method's parameters or return type.

Example:

Consider the following C code:

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

class Derived : public Base {
public:
    int foo(float x) override { ... } // Overrides the foo method from the Base class
};

class Derived2 : public Base {
public:
    int foo(int x) override { ... } // ERROR: Method signature does not match the base class
};</code>

In this example, the Derived class correctly overrides the foo method with the same signature as in the Base class. However, in the Derived2 class, the override is incorrect because the method signature changes the parameter type to an integer. The compiler will issue an error to prevent this mismatch.

By using the 'override' keyword, programmers can ensure that derived class methods are intended overrides and that their signatures align with the base class virtual methods. This helps prevent errors and ensures correct inheritance behaviors in C programs.

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