108 lines
1.7 KiB
C++
108 lines
1.7 KiB
C++
//
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// Created by light on 19-12-15.
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//
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#include <iostream>
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using namespace std;
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class shape {
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public:
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shape() { cout << "shape" << endl; }
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~shape() {
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cout << "~shape" << endl;
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}
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};
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class circle : public shape {
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public:
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circle() { cout << "circle" << endl; }
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~circle() {
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cout << "~circle" << endl;
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}
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};
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class triangle : public shape {
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public:
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triangle() { cout << "triangle" << endl; }
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~triangle() {
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cout << "~triangle" << endl;
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}
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};
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class rectangle : public shape {
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public:
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rectangle() { cout << "rectangle" << endl; }
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~rectangle() {
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cout << "~rectangle" << endl;
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}
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};
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class result {
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public:
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result() { puts("result()"); }
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~result() { puts("~result()"); }
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};
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result process_shape(const shape &shape1, const shape &shape2) {
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puts("process_shape()");
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return result();
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}
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class Base {
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public:
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Base() {
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cout << "Base()" << endl;
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}
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~Base() {
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cout << "~Base()" << endl;
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}
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};
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class Derived : public Base {
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public:
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Derived() {
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cout << "Derived()" << endl;
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}
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~Derived() {
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cout << "~Derived()" << endl;
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}
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};
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string f() { return "abc"; }
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void g() {
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const string &s = f(); // still legal?
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cout << s << endl;
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}
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Derived factory() {
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return Derived();
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}
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int main() {
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process_shape(circle(), triangle());
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cout << endl;
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// 临时对象延迟
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// result &&r = process_shape(circle(), triangle());
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// 临时对象延迟只对rvalue有用，而对xvalue无用！
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// result &&r = std::move(process_shape(circle(), triangle()));
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// const Base &b1 = factory();
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Base *b1 = new Derived;
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delete b1;
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cout<<endl;
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Derived d;
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Base &b2 =d;
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} |