43 lines
866 B
C++
43 lines
866 B
C++
// 静态类型转换
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#include <iostream>
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#include <cstring>
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#include <cstdlib>
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using namespace std;
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class A
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{
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public:
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int x;
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A(int x) : x(x) {}
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};
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class B : public A
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{
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public:
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int y;
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B(int x, int y) : A(x), y(y) {}
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};
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int main()
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{
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A *a = new A(5);
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B *b = new B(10, 20);
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A *c = static_cast<A *>(b); // 静态上行转换，子类指针向父类指针转换
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// cout << "a.x = " << a->x << endl;
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// cout << "b.x = " << b->x << ", b.y = " << b->y << endl;
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// cout << "b = " << b << endl;
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// cout << "c = " << c << endl;
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// cout << "c.x = " << c->x << endl;
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// B *b2 = static_cast<B *>(a); // 下行转换，父类指针向子类指针转换
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// B *b2 = (B *)a; // 强制下行转换，不安全
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// cout << "b2.x = " << b2->x << ", b2.y = " << b2->y << endl;
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delete a;
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delete b;
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return 0;
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}
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