15-1.txt

《C/C++完美演绎》源代码

/* 范例：15-1 构造方式1、2、3、4  */
#include <iostream.h>
struct hand
{
  int length;
};
class person
{
  private:
    char blood; char *name;
  public:
    hand *lefthand;
    hand *righthand;
    person(void)		/* 构造函数，可以有多个构造函数，以参数决定使用哪一个，
                         对象构造后自动执行 */
    { // new为C++配置内存的指令
    	lefthand = new hand;  righthand = new hand;
      	cout << "/* 构造方式1和3 */" << endl;
      	cout << "person class Constructor \n"; blood = 'O';
    }
    person(char *ch)	/* 析构函数，可以重载，以参数决定调用哪一个。new为C++
                        配置内存的指令 */
    {
      lefthand = new hand;  righthand = new hand;
      name = ch;
      cout << "\n/* 构造方式2和4 */" << endl;
      cout << "person(char *ch) class Constructor \n";
      cout << "------------------------\n";
    }
    ~person(void) 	/* 析构函数，不能overload，且无传入值，对象消失前自动执行 */
    {  // delete为C++删除内存的指令
       delete lefthand; delete righthand;
       cout << "person class Destructor \n";
    }
    void SetBlood(char a){ blood = a; }
    char GetBlood(void){ return blood;}
    void get_S_addr(){cout << "sca blood address=" \
                         << (void *)&blood <<endl;}
    void get_P_addr(){cout << "Peter blood address=" \
                         << (void *)&blood <<endl;}
    void ShowHandLen(void)
    {
       cout << "------------------------\n";
       cout << "hand left=" <<lefthand->length << "  hand right=" 
           << righthand->length << '\n';
    }
    void display_Pei(void)
    {cout << "人生目标:" << name << endl \
         << "name指针中存放的是ch的址: " \
         << (void*)name << endl << "name address = " \
         << &name << endl; }
};
  //---------------------------------------------------------------------------
void main()
{
  person sca;      // 直接操作方式构造对象,第一种构造方式
  //person sca = person();	/* 直接构造对象,第三种构造方式,这和构造方式一是相
                            同的,并调用其构造函数。 */
  sca.lefthand->length = 100;  sca.righthand->length = 150;
  sca.ShowHandLen();
  cout << "sca blood=" << sca.GetBlood() << '\n';
  cout << "sca address=" << &sca << endl;
  cout << "sca对象大小 = " << sizeof(sca) << "bytes" << endl;
  sca.get_S_addr();
  cout << "sca lefthand address=" << &sca.lefthand  << endl;
  cout << "sca righthand address=" << &sca.righthand  <<endl;
  cout << "sca.lefthand->length=" << &sca.lefthand->length << endl;
  cout << "sca.righthand->length=" << &sca.righthand->length << endl;
  char ch[20] = "Smile Always! ^_^";

  person pei_Pei(ch);   /* 第二种构造方式,构造对象并对应到ch相对应的构造函
                         数。*/
  //person pei_Pei = person(ch); //第四种构造方式, 且设定ch的初始值
  /* 构造对象时传参数给构造函数,定义字符字符串对象,并自动调用相对应的构造
     函数,这和第四种构造方式是一样的,所以也可以写成
person pei_pei = person(ch); */
  pei_Pei.display_Pei();	/* 调用pei_Pei的成员函数display_Pei(),显示字符串内容。 */
  cout << "ch size = " << sizeof(ch) <<endl;
  cout << "pei_Pei address=" << &pei_Pei << endl \
      << "char ch address = " << (void *)&ch \
      << endl <<"\npei_Pei对象的大小 = " \
      << sizeof(pei_Pei) << "bytes" << endl;
  cout << "ch: " << ch;
  getchar();
}

程序执行结果：
/* 构造方式1和3 */
person class Constructor
------------------------
hand left=100  hand right=150
sca blood=O
sca address=0065FDF4
sca对象大小 = 16bytes
sca blood address=0065FDF4
sca lefthand address=0065FDFC
sca righthand address=0065FE00
sca.lefthand->length=00682F00
sca.righthand->length=00682F10
/* 构造方式2和4 */
person(char *ch) class Constructor
------------------------
人生目标:Smile Always! ^_^
name指针中存放的是ch的址: 0065FDAC
name address = 0065FDE8
ch size = 20
pei_Pei address=0065FDE4
char ch address = 0065FDAC

pei_Pei对象的大小 = 16bytes
ch: Smile Always! ^_^