C++ Programming :: Using destructor


	Using destructor I have this class: class MyArray { public: MyArray(int a) : data(new int[a]){} ~MyArray() {delete[] data;} int& operator()(int a){ return data[a]; } int operator()(int a) const{ return data[a]; } private: int* data; }; int main() { MyArray myarr(5); return 0; } But when are the destructor called? - Hide quoted text - desktop wrote: > I have this class: > class MyArray { > public: > MyArray(int a) : data(new int[a]){} > ~MyArray() {delete[] data;} > int& operator()(int a){ > return data[a]; > } > int operator()(int a) const{ > return data[a]; > } > private: > int* data; > }; > int main() { > MyArray myarr(5); > return 0; > } > But when are the destructor called? The destructor is called implicitly when the object is distroyed - how it is destroyed does not matter. - Hide quoted text - desktop <f@sss.com> wrote: > I have this class: > class MyArray { > public: > MyArray(int a) : data(new int[a]){} > ~MyArray() {delete[] data;} > int& operator()(int a){ > return data[a]; > } > int operator()(int a) const{ > return data[a]; > } > private: > int* data; > }; > int main() { > MyArray myarr(5); > return 0; > } > But when are the destructor called? When "myarr" goes out of scope. On May 28, 10:05 am, desktop <f@sss.com> wrote: > I have this class: > class MyArray { > public: > MyArray(int a) : data(new int[a]){} MyArray(const int a) : data(new int[a]) { } - Hide quoted text - > ~MyArray() {delete[] data;} > int& operator()(int a){ > return data[a]; > } > int operator()(int a) const{ > return data[a]; > } > private: > int* data; > }; > int main() { > MyArray myarr(5); > return 0; > } > But when are the destructor called? The destructor is invoked when the object goes out of scope. In this case it happens when main returns. Add an output (std::cout << "~MyArray()";) to your d~tor to see it. Did you mean to write int& MyArray::operator[](int a) { ... } ? On May 28, 6:11 pm, Devon Null <theronnights@xgmailx.com> wrote: - Hide quoted text - > desktop wrote: > > I have this class: > > class MyArray { > > public: > > MyArray(int a) : data(new int[a]){} > > ~MyArray() {delete[] data;} > > int& operator()(int a){ > > return data[a]; > > } > > int operator()(int a) const{ > > return data[a]; > > } > > private: > > int* data; > > }; > > int main() { > > MyArray myarr(5); > > return 0; > > } > > But when are the destructor called? > The destructor is called implicitly when the object is distroyed - how > it is destroyed does not matter. btw, you can invoke destructor explicitly: myarr.~MyArr(); note: in member functions you should write 'this->~MyArray();'. not '~MyArray()' (without 'this->') - Hide quoted text - archimed7592 wrote: > On May 28, 6:11 pm, Devon Null <theronnights@xgmailx.com> wrote: >> desktop wrote: >> > I have this class: >> > class MyArray { >> > public: >> > MyArray(int a) : data(new int[a]){} >> > ~MyArray() {delete[] data;} >> > int& operator()(int a){ >> > return data[a]; >> > } >> > int operator()(int a) const{ >> > return data[a]; >> > } >> > private: >> > int* data; >> > }; >> > int main() { >> > MyArray myarr(5); >> > return 0; >> > } >> > But when are the destructor called? >> The destructor is called implicitly when the object is distroyed - how >> it is destroyed does not matter. > btw, you can invoke destructor explicitly: > myarr.~MyArr(); > note: in member functions you should write 'this->~MyArray();'. not > '~MyArray()' (without 'this->') Note however that this is almost never a good idea. On May 28, 3:02 pm, archimed7592 <archimed7@gmail.com> wrote: - Hide quoted text - > On May 28, 6:11 pm, Devon Null <theronnights@xgmailx.com> wrote: > > desktop wrote: > > > I have this class: > > > class MyArray { > > > public: > > > MyArray(int a) : data(new int[a]){} > > > ~MyArray() {delete[] data;} > > > int& operator()(int a){ > > > return data[a]; > > > } > > > int operator()(int a) const{ > > > return data[a]; > > > } > > > private: > > > int* data; > > > }; > > > int main() { > > > MyArray myarr(5); > > > return 0; > > > } > > > But when are the destructor called? > > The destructor is called implicitly when the object is distroyed - how > > it is destroyed does not matter. > btw, you can invoke destructor explicitly: and you can also jump off a skyscraper without a parachute. > myarr.~MyArr(); > note: in member functions you should write 'this->~MyArray();'. not > '~MyArray()' (without 'this->') If a user of the class needs to manage the lifetime of an object, he/ she should be doing it through dynamic allocation using smart pointers or new/delete. "desktop" <f@sss.com> wrote in message news:f3enk0$jgs$1@news.net.uni-c.dk... - Hide quoted text - >I have this class: > class MyArray { > public: > MyArray(int a) : data(new int[a]){} > ~MyArray() {delete[] data;} > int& operator()(int a){ > return data[a]; > } > int operator()(int a) const{ > return data[a]; > } > private: > int* data; > }; > int main() { > MyArray myarr(5); > return 0; Here is where the destructor is called. This return statement is exiting the function main, myarr goes out of scope, so it's destructor is called. - Hide quoted text - > } > But when are the destructor called?