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POArray objects initialization whose class has some ctor / dtor
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  1. POArray objects initialization whose class has some ctor / dtor
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    copied!<p>I would like to realize array objects initialization by using the initialization statement as follows.</p> <pre><code>TestClass array[5] = { TestClass("test1"), TestClass("test2"), TestClass("test3"), TestClass("test4"), TestClass("test5") }; </code></pre> <p>According to some authoritative book like ARM (annotated reference manual) for C++, it seems that it says that this is the way to initialize object array which has constructor / destructor. Following this, I've just created the following sample code and see what happens.</p> <pre><code>#include &lt;iostream&gt; #include &lt;sstream&gt; #include &lt;string&gt; class TestClass { public: TestClass(const char* name) : name_(name) { std::cout &lt;&lt; "Ctor(const char*) : " &lt;&lt; name_ &lt;&lt; std::endl; } ~TestClass() { std::cout &lt;&lt; "Dtor() : " &lt;&lt; name_ &lt;&lt; std::endl; } TestClass() : name_("") { } void print() { std::cout &lt;&lt; "obj:" &lt;&lt; name_ &lt;&lt; std::endl; } private: TestClass(const TestClass&amp; rhs); std::string name_; }; int main() { TestClass array[5] = { TestClass("test1"), TestClass("test2"), TestClass("test3"), TestClass("test4"), TestClass("test5") }; for (unsigned int i = 0; i &lt; sizeof(array)/sizeof(array[0]); ++i) { array[i].print(); } return EXIT_SUCCESS; } </code></pre> <p>As for the first trial to compile the above source code using GNU GCC (4.1.2), it failed by generating something like the following.</p> <pre><code>error: ‘TestClass::TestClass(const TestClass&amp;)’ is private </code></pre> <p>So I understood that this means that in order to allow object array initialization, it would require 'copy constructor'. Then I tried to compile the above code by introducing user-defined (public) copy constructor as follows.</p> <pre><code>TestClass::TestClass(const TestClass&amp; rhs) : name_(rhs.name_) { std::cout &lt;&lt; "Copy Ctor : " &lt;&lt; name_ &lt;&lt; std::endl; } </code></pre> <p>I could successfully compile the source code. However, when I execute the program which has been built the above, I got the following output.</p> <pre><code>Ctor(const char*) : test1 Ctor(const char*) : test2 Ctor(const char*) : test3 Ctor(const char*) : test4 Ctor(const char*) : test5 obj:test1 obj:test2 obj:test3 obj:test4 obj:test5 Dtor() : test5 Dtor() : test4 Dtor() : test3 Dtor() : test2 Dtor() : test1 </code></pre> <p>What I'm curious to know is the following,</p> <ol> <li><p>Why we cannot make the copy constructor declared as private?</p></li> <li><p>Why the user-defined copy constructor is not invoked (I expected that the output should have included "Copy Ctor : xxxx" somewhere. But I couldn't get that. So I understood the user-defined copy constructor has not been invoked.)</p></li> </ol> <p>Actually, I'm not really sure whether the above is specific to GNU GCC or this is C++ language specification... It would be appreciated if some of you could give me the correct pointer on the above.</p>
 

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