Lect18
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Пример1
class Hold { |
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char *ptr; |
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public: |
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Hold(char *str) { |
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cout << "Constructor." << endl; |
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ptr = new char[strlen(str)+1] ; |
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strcpy(ptr, str) ; |
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cout << "Constructor: throwing exception..." |
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<< endl; |
} |
throw "Exception!"; |
~Hold() { |
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cout << "Destructor.\n" << endl; |
} |
delete [ ] ptr; |
void Show(){ |
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} |
cout << "My contents: " << ptr << endl; |
}; |
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Пример1
int main() {
try { Hold h = "Some string."; } catch(char *str) {
}
printf("Message caught: %s\n", str);
printf("Exiting main...\n"); cin.ignore();
}
return 0;
Результат |
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Constructor. |
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Global new[]. |
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Constructor: throwing exception... |
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Message caught: Exception! |
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Exiting main... |
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Пример2
class A { public:
A(string const& name): m_name(name)
}{ cout << "A::A(" << m_name << ")"<<endl;
~A()
{} cout << "A::~A(" << m_name << ")"<<endl;
private:
};
string m_name;
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Пример2 |
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Нехватка памяти и |
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выбросисключения |
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class B { |
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std::bad_alloc |
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public: |
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B(string const& name, size_t size) |
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:m_a(name) |
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,m_pData(new |
int[size]) |
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,m_size(size) { |
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} cout << "B::B(" << m_size << ")" << endl; |
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~B() { |
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delete [] m_pData; |
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cout << "B::~B(" << m_size << ")"<< endl; |
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} |
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Результат: |
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private: |
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A m_a; |
A::A(Test) |
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size_t m_size; |
A::~A(Test) |
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int * m_pData; |
Error: bad |
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}; |
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allocation |
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Выбросисключенияв деструкторе
Недопускайтевыбросаисключенийв деструкторахобъектов!
ВC++ выбросисключенияв деструктореприводиткаварийному завершениюработыпрограммы!
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Спасибозавнимание!
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