#include <iostream>
using namespace std;
class MyClassA
{
public:
  MyClassA()
  {
    cout << "无参构造函数调用" << endl;
  }
  MyClassA(int a)
  {
    this->a = a;
    cout << "有参构造函数调用" << endl;
  }
  ~MyClassA()
  {
    cout << "析构函数调用" << endl;
  }
public:
  void SetA(int a)
  {
    this->a = a;
  }
  void PrintA()
  {
    cout << "a = " << a << endl;
  }
private:
  int a;
};
//使用new和delete分配基本数据类型
void FuncTest1()
{
  //malloc free  库函数
  int* a = (int*)malloc(sizeof(int) * 1);
  *a = 6;
  cout << *a << endl;
  free(a);
  //new delete  运算符
  int* b = new int;
  *b = 6;
  cout << *b << endl;
  delete b;
  //new的同时初始化
  int* c = new int(6);
  cout << *c << endl;
  delete c;
}
//new delete 分配数组
void FuncTest2()
{
  char* a = (char*)malloc(sizeof(char) * 6);
  *a = 'a';
  cout << a[0] << endl;
  free(a);
  char* b = new char[6];
  *b = 'b';
  cout << b[0] << endl;
  delete[] b;
}
//分配类对象
void FuncTest3()
{
  MyClassA* a = (MyClassA*)malloc(sizeof(MyClassA));
  a->SetA(7);
  (*a).PrintA();
  free(a);
  MyClassA* b = new MyClassA; //调用无参构造函数
  b->SetA(8);
  b->PrintA();
  delete b; //调用析构函数
  MyClassA* c = new MyClassA(5); //调用有参构造函数
  c->PrintA();
  delete c; //调用析构函数
}
//混搭使用
void FuncTest4()
{
  MyClassA* a = (MyClassA*)malloc(sizeof(MyClassA)); //不会调用无参构造函数
  a->SetA(7);
  (*a).PrintA();
  delete a; //调用析构函数
  MyClassA* b = new MyClassA; //调用无参构造函数
  b->SetA(8);
  b->PrintA();
  free(b); //不会调用析构函数
}
int main()
{
  FuncTest1();
  FuncTest2();
  FuncTest3();
  FuncTest4();
  std::cout << "Hello World!\n";
  system("pause");
  return 0;
}