C++中复制构造函数和隐式转换
隐式转换可能发生在对象的初始化中（包括由赋值间接产生的初始化），不可能由赋值直接产生
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#include <iostream> |
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using namespace std; |
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class MyClass |
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{ |
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public: |
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MyClass(); |
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MyClass(int i); |
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MyClass(const MyClass &c); |
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~MyClass(); |
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MyClass & operator = (const MyClass &c); |
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private: |
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int m_i; |
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}; |
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MyClass::MyClass() |
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{ |
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m_i = 0; |
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cout << "MyClass()" << endl; |
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} |
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MyClass::MyClass(int i) |
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{ |
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m_i = i; |
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cout << "MyClass(int i)" << endl; |
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} |
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MyClass::MyClass(const MyClass &c) |
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{ |
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m_i = c.m_i; |
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cout << "MyClass(const MyClass &c)" << endl; |
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} |
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MyClass::~MyClass() |
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{ |
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} |
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MyClass & MyClass::operator =(const MyClass &c) |
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{ |
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m_i = c.m_i; |
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cout << "operator =(const MyClass &c)" << endl; |
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return *this; |
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} |
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int main() |
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{ |
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MyClass c1; // MyClass() |
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cout << "-------------------------------" << endl; |
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MyClass c2 = 2; // MyClass(int i) 隐式转换 |
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cout << "-------------------------------" << endl; |
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MyClass c3 = c2;// MyClass(const MyClass &c) 隐式转换 |
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cout << "-------------------------------" << endl; |
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c1 = 2; // MyClass(int i) 隐式转换 |
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// operator =(const MyClass &c) 无隐式转换 |
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cout << "-------------------------------" << endl; |
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c3 = c2; // operator =(const MyClass &c) 无隐式转换 |
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cout << "-------------------------------" << endl; |
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return 0; |
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} |
结果：
MyClass()
-------------------------------
MyClass(int i)
-------------------------------
MyClass(const MyClass &c)
-------------------------------
MyClass(int i)
operator =(const MyClass &c)
-------------------------------
operator =(const MyClass &c)
-------------------------------
