C++构造及析构函数调用问题

//析构函数在对象的生命周期结束时调用，例如函数内局部对象是在函数结束时调用，堆内存中对象是在delete时调用。

//<span style="font-family: Arial, Helvetica, sans-serif;">构造函数看前一篇。</span>

</pre><pre code_snippet_id="515346" snippet_file_name="blog_20141111_4_5506757" name="code" class="cpp">// PRC TRY.cpp : 定义控制台应用程序的入口点。//// PRC TRY.cpp : Defines the entry point for the console application.//#include "stdafx.h"#include<iostream>#include<string>using namespace std;class Demo{public:Demo(int a=0,int b=0){cout<<"调用无参构造函数"<<endl;}Demo(const Demo &x){cout<<"调用拷贝构造函数"<<endl;}~Demo(){cout<<"调用析构函数"<<endl;}};Demo userCode(Demo b){Demo c(b);return c;}int main(int argc, char* argv[]){Demo a,d;cout<<"---------"<<endl;d = userCode(a);cout<<"---------"<<endl;return 0;}<pre name="code" class="cpp">

运行结果：

// PRC TRY.cpp : 定义控制台应用程序的入口点。//// PRC TRY.cpp : Defines the entry point for the console application.//#include<iostream>using namespace std;//最好能单步调试，看得更明显class Test{public:Test(){cout<<"Constructor!"<<endl;}~Test(){cout<<"Destructor!"<<endl;}};int main(){Test* pt;pt = new Test;//此处调用构造函数delete pt;//调用析构函数return 0;}

运行结果：