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C Detailed explanation of function parameters: The role of runtime type identification in parameter passing
In C, function parameter passing can be passed by value , reference passing or pointer passing implementation. Each delivery method has its own advantages and disadvantages.
Run-Time Type Identification (RTTI) is a mechanism in C to obtain the type of an object at runtime. It allows us to determine the actual type of an object even if the object is stored in a base class pointer or reference.
By using RTTI, we can achieve the following functions:
Using RTTI in parameter passing
In function parameter passing, RTTI can be used to implement polymorphism. Polymorphism allows us to call methods of a derived class through a base class pointer or reference. In order to achieve polymorphism, we need the following steps:
Practical Case
Consider the example in the following code:
#include <iostream> using namespace std; class Base { public: virtual void print() { cout << "Base class print" << endl; } }; class Derived : public Base { public: void print() { cout << "Derived class print" << endl; } }; void printObject(Base* obj) { // 使用 RTTI 确定对象的实际类型 if (dynamic_cast<Derived*>(obj)) { // 如果对象是派生类类型,调用派生类方法 static_cast<Derived*>(obj)->print(); } else { // 否则,调用基类方法 obj->print(); } } int main() { Base* baseObj = new Base(); printObject(baseObj); // 输出:Base class print Derived* derivedObj = new Derived(); printObject(derivedObj); // 输出:Derived class print return 0; }
In this case, the printObject
function Use RTTI to determine the actual type of the object passed to it. If the object is of a derived class type, it calls the derived class method. Otherwise, it calls the base class method.
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