inline
//inline函数可以有声明和实现，但是必须在同一文件
//inline函数不能分成头文件和实现文件
inline int add(int x, int y)
{ //一般不要放循环语句
return x + y;
}
//如果是自定义类类型，都要大写首字母
class Computer
{
public://public成员可以在类之外访问
//public成员称为类对外的接口、功能、服务
//对成员函数采用驼峰方式进行命名
void setBrand(const char * brand)
{
strcpy(_brand, brand);
}
void setPrice(double price)
{
_price = price;
}
//protected://保护成员不能在类之外访问
void print()
{
cout << "brand:" << _brand << endl
<< "price:" << _price << endl;
}
//私有成员尽量放到类的底部
private://私有的成员不能在类之外访问
char _brand[20];//brand_ / m_brand
double _price;
};
类的声明和定义
//类的声明
class Computer
{
//class的默认访问权限是private的
public:
void setBrand(const char * brand);
void setPrice(double price);
void print();
//通过private关键字表现封装的特性
private://类对象占据的空间只与数据成员有关，
//成员函数存储在程序代码区, 不会占据对象的空间
char _brand[20];
double _price;
};
//类的实现
void Computer::setBrand(const char * brand)
{
strcpy(_brand, brand);
}
void Computer::setPrice(double price)
{
_price = price;
}
void Computer::print()
{
cout << "brand:" << _brand << endl
<< "price:" << _price << endl;
}
构造函数析构函数
class Computer
{
public:
Computer(const char * brand, double price)
: _brand(new char[strlen(brand) + 1]()) //浅拷贝, 只传地址
, _price(price)
{
strcpy(_brand, brand);
cout << "Computer(const char *, double)" << endl;
}
void print()
{
cout << " brand:" << _brand << endl
<< " price:" << _price << endl;
}
//对象销毁的过程中会自动调用析构函数
//
//问题: 执行了析构函数就是销毁了对象
#if 0
void release()
{
delete [] _brand;
}
#endif
~Computer()
{ //析构函数的作用：是用来回收对象申请的资源
if(_brand) {
delete [] _brand;
_brand = nullptr;//NULL
}
cout << "~Computer()" << endl;
}
private:
char * _brand;
double _price;
};
//Computer pc2("Xiaomi", 7500);
int test0(void)
{
{
Computer pc1("MateBook", 6666);
cout << ">> pc1: " << endl;
pc1.print();
}
cout << ">> pc2: " << endl;
// pc2.print();
//堆空间的对象的销毁，需要手动执行
Computer * pc3 = new Computer("Thinkpad", 7777);
cout << ">> pc3: " << endl;
pc3->print();
delete pc3;//不要忘了, 执行delete表达式的过程中，就会调用析构函数
static Computer pc4("Macbook pro", 20000);
cout << ">> pc4: " << endl;
pc4.print();
return 0;
}
void test1()
{
Computer * pc3 = new Computer("Thinkpad", 7777);
cout << ">> pc3: " << endl;
pc3->print();
pc3->~Computer();//该语句被执行之后，对象是没有被销毁的
delete pc3;
}
void test2()
{
Computer pc1("MateBook", 6666);
cout << ">> pc1: " << endl;
pc1.print();
pc1.~Computer();//析构函数可以主动调用，但不推荐这样做
//析构函数应该让其自动执行
//pc1.release();
}
拷贝构造函数
class Computer
{
public:
Computer(const char * brand, double price)
: _brand(new char[strlen(brand) + 1]())
, _price(price)
{
strcpy(_brand, brand);
cout << "Computer(const char *, double)" << endl;
}
//系统提供的 已经不能满足需求
#if 0
Computer(const Computer & rhs)
: _brand(rhs._brand)//浅拷贝, 只传地址
, _price(rhs._price)
{
cout << "Computer(const Computer&)" << endl;
}
#endif
Computer(const Computer & rhs)
: _brand(new char[strlen(rhs._brand) + 1]())
, _price(rhs._price)
{
strcpy(_brand, rhs._brand);
cout << "Computer(const Computer&)" << endl;
}
void print()
{
printf(" brand = %p\n", _brand);
cout << " brand:" << _brand << endl
<< " price:" << _price << endl;
}
~Computer()
{
delete [] _brand;
cout << "~Computer()" << endl;
}
private:
char * _brand;
double _price;
};
void test0()
{
Computer pc1("MateBook", 6666);
cout << ">> pc1: " << endl;
pc1.print();
//用一个已经存在的对象初始化另一个新对象
Computer pc2 = pc1;
cout << ">> pc2: " << endl;
pc2.print();
}
原文地址：https://www.cnblogs.com/Davirain/p/11770257.html