[英]no matching function for call to ..constructor
I am trying to compile a code that involves inheritance. 我正在尝试编译涉及继承的代码。
#include "MapEntityClass.h"
class RectangularEntityClass:public MapEntityClass
{
public:
void drawOnMap(MapClass *mapObj) const;
protected:
};
The parent class is MapEntityClass, which does not have a default constructor, but has a value constructor. 父类是MapEntityClass,它没有默认构造函数,但具有值构造函数。 When I compile, I get the following error:
编译时,出现以下错误:
RectangularEntityClass.h: In constructor ‘RectangularEntityClass::RectangularEntityClass()’:
RectangularEntityClass.h:12:7: error: no matching function for call to ‘MapEntityClass::MapEntityClass()’
class RectangularEntityClass:public MapEntityClass
^
RectangularEntityClass.h:12:7: note: candidates are:
In file included from main.cpp:1:0:
MapEntityClass.h:32:5: note: MapEntityClass::MapEntityClass(const PixelLocationClass&, const ColorClass&)
MapEntityClass(
^
MapEntityClass.h:32:5: note: candidate expects 2 arguments, 0 provided
Any idea what is wrong? 知道有什么问题吗?
In inheritance, the subclass need not have a constructor only if parent class doesn't have a constructor or only default constructor. 在继承中,仅当父类没有构造函数或只有默认构造函数时,子类才不需要构造函数。
In any case, if parent class happens to have a parameterized constructor, the subclass should have a parameterized constructor which should invoke the parent class constructor. 无论如何,如果父类碰巧具有参数化的构造函数,则子类应具有参数化的构造函数,该参数化构造函数应调用父类的构造函数。
Example: 例:
class A {
int aVal;
public:
A(int);
};
A::A(int aVal)
{
this->aVal = aVal;
}
class B : public A {
int bVal;
public:
B(int, int)
};
B::B(int aVal, int bVal) : A(aVal)
{
this->bVal = bVal;
}
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