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72 lines
1.4 KiB
C++
72 lines
1.4 KiB
C++
#include <iostream>
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#include <string>
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class mybase {
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protected:
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std::string ids;
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public:
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mybase(std::string ids)
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: ids(ids) {}
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virtual void foo() {
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std::cout << "i'm a mybase! ids: " << ids << std::endl;
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}
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};
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class myclass : public mybase {
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public:
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myclass(std::string ids)
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: mybase(ids) {}
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void foo() {
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std::cout << "i'm a myclass! ids: " << ids << std::endl;
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}
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};
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void nocast(myclass* x) {
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x->foo();
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}
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void ccast(void* x) {
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// C-style cast, guess that's not the C++ way, but works.
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myclass* foo = (myclass*) x;
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foo->foo();
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}
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void staticcast(void* x) {
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// C++ static_cast. When I *know* it's myclass*, and want to revert an
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// implicit conversion.
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myclass* foo = static_cast<myclass*>(x);
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foo->foo();
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}
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void dynamiccast(mybase* x) {
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// C++ dynamic_cast.
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if (myclass* foo = dynamic_cast<myclass*>(x)) {
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// only if x is actually a myclass*, this gets executed.
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foo->foo();
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}
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}
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int main() {
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myclass a("a");
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mybase base("base");
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std::cout << "== nocast" << std::endl;
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nocast(&a);
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// nocast(&base); <- Does not compile
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std::cout << "== ccast" << std::endl;
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ccast(&a);
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ccast(&base); // XXX actually works!
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std::cout << "== staticcast" << std::endl;
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staticcast(&a);
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staticcast(&base); // XXX actually works!
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std::cout << "== dynamiccast" << std::endl;
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dynamiccast(&a);
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dynamiccast(&base);
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}
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