sairate
4108f6c42d
- 新增现代 C++ 教程的 Preface 章节，包括英文和中文版本 - 添加 C++ Primer 练习代码 - 新增 Learn C++ 教程的 C++ 开发简介章节 - 添加头文件解析文档 - 更新 mkdocs.yml，包含新教程的目录结构 - 修改项目设置，使用 Python 3.10环境
40 lines
1.0 KiB
C++
40 lines
1.0 KiB
C++
//
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// 3.5.move.semantics.cpp
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// modern c++ tutorial
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//
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// created by changkun at changkun.de
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// https://github.com/changkun/modern-cpp-tutorial
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//
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#include <iostream>
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class A {
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public:
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int *pointer;
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A():pointer(new int(1)) {
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std::cout << "construct" << pointer << std::endl;
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}
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A(A& a):pointer(new int(*a.pointer)) {
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std::cout << "copy" << pointer << std::endl;
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} // meaningless object copy
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A(A&& a):pointer(a.pointer) {
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a.pointer = nullptr;
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std::cout << "move" << pointer << std::endl;
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}
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~A(){
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std::cout << "destruct" << pointer << std::endl;
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delete pointer;
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}
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};
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// avoid compiler optimization
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A return_rvalue(bool test) {
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A a,b;
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if(test) return a; // equal to static_cast<A&&>(a);
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else return b; // equal to static_cast<A&&>(b);
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}
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int main() {
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A obj = return_rvalue(false);
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std::cout << "obj:" << std::endl;
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std::cout << obj.pointer << std::endl;
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std::cout << *obj.pointer << std::endl;
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return 0;
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} |