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C Equivalent to Java's Instanceof: dynamic_cast and Alternative Approaches
Java's instanceof operator allows you to check if an object is an instance of a specific class or its subclasses. In C , you can achieve similar functionality using dynamic_cast.
<code class="cpp">if (NewType* v = dynamic_cast<NewType*>(old)) { // Cast succeeded, old is a NewType object v->doSomething(); }</code>
This approach requires runtime type information (RTTI) to be enabled in your compiler. However, dynamic_cast can come at a performance cost.
Alternative Approaches:
<code class="cpp">switch (old->getType()) { case BOX: // old is a Box object break; case SPECIAL_BOX: // old is a SpecialBox object break; }</code>
This approach does not require RTTI but is not suitable for multi-level inheritance.
Note: Consider the necessity of dynamic type checking as it can indicate design issues. Alternatives like virtual functions or the enum approach may provide better design and performance in many cases.
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