小代码

#include"sts.h"

#if(0)
class Base
{
public:
void f(int x){cout<<"Base::f(int)"<<x<<endl;}
void f(float x){cout<<"Base::f(float)"<<x<<endl;}
//成员函数重载特征：相同的名字和范围，参数不同virtual关键字可有可无

virtual  void g(void){cout<<"Base::g(void)"<<endl;}
};
class Derived:public Base
{
public:
virtual void g(void){cout<<"Drived::g(void)"<<endl;}
//覆盖不同的范围参数名字均相同，必须要有virtual关键字
};
int main()
{
Derived d;
Base *pb=&d;
pb->f(42);   //Base::f(int)42
pb->f(4.2f); //Base::f(float)4.2
pb->g();     //Drived::g(void)
return 0;
}
#endif
#if(0)
class Base2
{
public:
virtual  void f(float x){cout<<"B::f(float)"<<x<<endl;}
void g(float x){cout<<"B::g(float)"<<x<<endl;}
void h(float x){cout<<"B::h(float)"<<x<<endl;}
};
class Derived:public Base2
{
public:
virtual  void f(float x){cout<<"D::f(float)"<<x<<endl;}//覆盖
void g(float x){cout<<"D::g(float)"<<x<<endl;}//隐藏
void h(float x){cout<<"D::h(float)"<<x<<endl;}//隐藏
};
int main()
{
Derived d;
Base2 *pb=&d;
Derived *pd=&d;
pb->f(1.1f);
pd->f(2.2f);
pb->g(3.3f);
pd->g(4.4f);
pb->h(5.5f);
pd->h(6.6f);
/*
D::f(float)1.1
D::f(float)2.2
B::g(float)3.3
D::g(float)4.4
B::h(float)5.5
D::h(float)6.6
*/
return 0;
}
#endif
#if(0)

class b { public:void f(int x);};
//class d:public b{public:void f(char *str);};
class d:public b{public:void f(char *str);void f(int x){b::f(x);}};
void test(void){d *pd=new d;pd->f(10);}/*编译报错*/
int main()
{ cout<<"wzzx"<<endl;
test();
// 修改class b不同结果
return 0;
}

#endif
#if(0)
//声明  可有缺省  从后往前依次缺省 缺省仅书写简单，函数易用
void out(int x);
void out(int x,float y=0.0);//
//定义  不可有缺省
void out(int x){cout<<"out int "<<x<<endl;}
void out(int x,float y){cout<<"out int and float "<<x<<y<<endl;}
int main()
{ cout<<"wzzx"<<endl;
int x=1;float y=1.234;
//out(x);
// is ambiguous,产生二义性
out(x,y);
return 0;
}

#endif
#if(0)
#define max1(a,b) (a)>(b)?(a):(b)
#define max2(a,b) ((a)>(b)?(a):(b))
int main()
{
int x=1;int y=2;
cout<<(max1(x,y)+2)<<endl;
//(x)>(y)?(x):(y)+2
cout<<(max2(x,y)+2)<<endl;
//(x)>(y)?(x):(y)+2
cout<<(max1(x++,y)+2)<<endl;
//(x)>(y)?(x):(y)+2
cout<<(max2(x++,y)+2)<<endl;

return 0;
}

#endif
// 内联 不能出现在长函数和循环函数前

#if(0)
class b{public:virtual ~b(){cout<<"~b"<<endl;}};
class d:public b{public:virtual ~d(){cout<<"~d"<<endl;}};
int  main()
{
b *pb=new d;
delete pb;
//~d
//~b

return 0;
}

#endif
#if(1)
/*
class string
{
public: string(const char *str=NULL);
string(const string & other);
~string(void);
string &operate =(const string & other);
private:   char  *m_data;
};
string::string(const char *str)
{
if(str==NULL){m_data=new char[1];*m_data='\0';}
else    {int length =strlen(str);m_data=new char[length+1];strcpy(m_data,str);}
}
string::~string(void){delete [] m_data;}
*/
int main()
{
//9.6----9.7
return 0;
}
#endif
#if(0)

#endif