42 lines
1.2 KiB
C++
42 lines
1.2 KiB
C++
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// 请简述static_cast、dynamic_cast和reinterpret_cast的区别，并给出示例代码进行说明。
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// dynamic_cast :
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// 动态转换，用于多态类之间的转换，即在基类指针或引用和派生类指针或引用之间进行转换。它在运行时进行类型检查，如果转换是安全的，则返回转换后的指针或引用；如果转换不安全，则返回空指针或引用。dynamic_case 只能用于具有虚函数的类之间的转换。
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#include <iostream>
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using namespace std;
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class Base
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{
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public:
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virtual void foo() { cout << "基类 foo() 函数" << endl; }
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};
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class Derived : public Base
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{
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public:
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void bar() { cout << "派生类 bar() 函数" << endl; }
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void foo() { cout << "派生类 foo() 函数" << endl; }
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};
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int main()
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{
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Base *p = new Derived();
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Derived *dp = dynamic_cast<Derived *>(p); // 向下转换，安全
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dp->bar(); // 可以调用派生类的成员函数
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dp->foo(); // 可以调用派生类的虚函数
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Base *p1 = new Base();
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Derived *dp1 = dynamic_cast<Derived *>(p1); // 向下转换，不安全
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dp1->bar();
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// dp1->foo();
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Derived *dp2 = new Derived();
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Base *p2 = dynamic_cast<Base *>(dp2); // 向上转换，安全
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p2->foo();
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return 0;
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}
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