C/C++编程风格//1.C风格(结构化程序设计):数据和函数(操作)没有任何关联性typedef struct Point3d{ float x; float y; float z;} Point3d_t;voidPoint3d_print(const Point3d_t *pd
C/C++ 编程风格
//1.C风格(结构化程序设计):数据和函数(操作)没有任何关联性
typedef struct Point3d
{
float x;
float y;
float z;
} Point3d_t;
void
Point3d_print(const Point3d_t *pd)
{
printf("%g,%g,%g
",pd->x,pd->y,pd->z);
}
//2.基于对象(Object-Base):提供抽象数据类型(ADT)来支持封装
class Point3d
{
friend ostream &operator<<(ostream &os,const Point3d &pt);
public:
Point3d(float x = 0.0,float y = 0.0,float z = 0.0):
_x(x),_y(y),_z(z) {}
float x()
{
return _x;
}
float y()
{
return _y;
}
float z()
{
return _z;
}
void x(float xval)
{
_x = xval;
}
//etc...
private:
float _x;
float _y;
float _z;
};
inline ostream &
operator<<(ostream &os,const Point3d &pt)
{
return os << "( " << pt._x << "," << pt._y << ","
<< pt._z << " )";
}
//3.面向对象(Object-Oriented-Model):提供继承和多态
class Point
{
public:
Point(float x = 0.0):
_x(x) {}
float x()
{
return _x;
}
void x(float xValue)
{
_x = xValue;
}
protected:
float _x;
};
class Point2d : public Point
{
public:
Point2d(float x = 0.0,float y = 0.0):
Point(x),_y(y) {}
float y()
{
return _y;
}
void y(float yValue)
{
_y = yValue;
}
protected:
float _y;
};
class Point3d : public Point2d
{
friend inline ostream &
operator<<(ostream &os,const Point3d &pt);
public:
Point3d(float x = 0.0,float z = 0.0):
Point2d(x,y),_z(z) {}
float z()
{
return _z;
}
void z(float zValue)
{
_z = zValue;
}
private:
float _z;
};
inline ostream &
operator<<(ostream &os,"
<< pt._z << " )";
}
//4.面向泛型:提供模板提供类型无关化的编程风格
//示例(1):仅提供类型参数化
template <typename Type>
class Point3d
{
public:
Point3d(Type x = 0.0,Type y = 0.0,Type z = 0.0):
_x(x),_z(z) {}
Type x()
{
return _x;
}
Type y()
{
return _y;
}
Type z()
{
return _z;
}
void x(const Type &xval)
{
_x = xval;
}
//etc...
private:
Type _x;
Type _y;
Type _z;
};
//示例(2):同时提供类型和数目(int dim)参数化
template <typename Type,int dim>
class Point
{
public:
Point() {}
Point(Type coordes[dim])
{
for (int index = 0; index < dim; ++index)
{
_coordes[index] = coordes[index];
}
}
const Type &operator[](int index) const
{
assert(index < dim && index >= 0);
return _coordes[index];
}
private:
Type _coordes[dim];
};
template <typename Type,int dim>
inline ostream &operator<<(ostream &os,const Point< Type,dim > &pt)
{
os << "( ";
for (int i = 0; i < dim; ++i)
os << pt[i] << ",";
os << ")";
return os;
}
//测试
int array[] = {11,12,333};
Point<int,3> point(array);
cout << point << endl;
cout << point[2] << endl;
小结:C++加上封装的布局本钱
(1)3个data-member[数据成员]直接内含在每个class-object[对象]当中,犹如C-Struct1样;
(2)Member-function虽然存在于class的声明中, 却不出现在object当中, 每个non-inline member function[非inline的成员函数]只会诞生1个函数实体;
(3)而inline member function会在其每个使用者身上产生1个函数实体.
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