编辑:在底部张贴修复代码。谢谢大家的帮助!
我正在学习c++,在继承方面遇到了麻烦。我已经搜索和搜索,并尝试了任何我可以,但我不能得到这个代码来编译,同时保留我想要它的功能。
我觉得我犯了一个愚蠢的错误,或者我只是错过了一些大的概念,但如果有人能看看它,我真的很感激!
如果我注释掉StarSystem构造函数中创建对象的3行,那么它就会编译,所以我知道这与问题有关。
#include <iostream>
#include <vector>
#include <string>
#include <stdlib.h>
#include <time.h>
using namespace std;
class SystemBody
{
public:
SystemBody();
int systembodyindex;
int starsystemindex;
SystemBody(int systembodyindex, int starsystemindex)
{
cout << "StarSystem " << starsystemindex << ": creating empty SystemBody " << systembodyindex << endl;
}
};
class Star : public SystemBody
{
public:
Star();
string startype;
Star(int systembodyindex, int starsystemindex)
{
cout << "StarSystem " << starsystemindex << ": converting empty SystemBody into Star " << systembodyindex << endl;
}
};
class Planet : public SystemBody
{
public:
Planet();
string planettype;
Planet(int systembodyindex, int starsystemindex)
{
cout << "StarSystem " << starsystemindex << ": converting empty SystemBody into Planet " << systembodyindex << endl;
}
};
class ExitNode : public SystemBody
{
public:
ExitNode();
vector<int> connectedindexlist;
ExitNode(int systembodyindex, int starsystemindex)
{
cout << "StarSystem " << starsystemindex << ": converting empty SystemBody into Exit Node " << systembodyindex << endl;
}
};
class StarSystem
{
public:
StarSystem();
int starsystemindex;
vector<StarSystem> connectedlist;
vector<Planet> planetlist;
StarSystem(int index)
{
starsystemindex = index;
cout << "--Creating StarSystem: " << starsystemindex << endl;
int numberofbodies = (rand() % 4) + 2;
for ( int i = 0; i < numberofbodies; i +=1 )
{
if ( i == 0 )
{
Star body(i, starsystemindex);
}
else if ( i == numberofbodies )
{
ExitNode body(i, starsystemindex);
}
else
{
Planet body(i, starsystemindex);
}
}
}
void addConnection(StarSystem connectedstarsystem)
{
cout << "--StarSystem " << starsystemindex << ": Adding connection to StarSystem " << connectedstarsystem.starsystemindex << endl;
connectedlist.push_back(connectedstarsystem);
}
};
int main()
{
srand(time(0));
StarSystem starsystem0(0);
return 0;
}
编辑:感谢大家的帮助!只是在这里张贴固定的代码,以防将来有人可能会发现这有用。
#include <iostream>
#include <vector>
#include <string>
#include <stdlib.h>
#include <time.h>
using namespace std;
class SystemBody
{
public:
int systembodyindex;
int starsystemindex;
SystemBody ( )
{
cout << "----SystemBody BEING CREATED WITH NO PARAMETERS" << endl;
}
SystemBody ( int bodyindex, int systemindex )
{
systembodyindex = bodyindex;
starsystemindex = systemindex;
cout << "----StarSystem " << starsystemindex << ": creating empty SystemBody " << systembodyindex << endl;
}
};
class Star : public SystemBody
{
public:
Star ( int bodyindex, int systemindex ) : SystemBody ( bodyindex, systemindex )
{
cout << "----StarSystem " << starsystemindex << ": converting empty SystemBody into Star " << systembodyindex << endl;
}
};
class Planet : public SystemBody
{
public:
Planet ( int bodyindex, int systemindex ) : SystemBody ( bodyindex, systemindex )
{
cout << "----StarSystem " << starsystemindex << ": converting empty SystemBody into Planet " << systembodyindex << endl;
}
};
class ExitNode : public SystemBody
{
public:
ExitNode ( int bodyindex, int systemindex ) : SystemBody ( bodyindex, systemindex )
{
cout << "----StarSystem " << starsystemindex << ": converting empty SystemBody into ExitNode " << systembodyindex << endl;
}
};
class StarSystem
{
public:
int starsystemindex;
vector<StarSystem> connectedlist;
vector<Planet> planetlist;
StarSystem ( int index )
{
starsystemindex = index;
cout << "--Creating StarSystem: " << starsystemindex << endl;
int numberofbodies = (rand() % 4 ) + 2;
for ( int i = 0; i <= numberofbodies; i +=1 )
{
if ( i == 0)
{
Star body(i, starsystemindex);
}
else if ( i == numberofbodies )
{
ExitNode body(i, starsystemindex);
}
else
{
Planet body(i, starsystemindex);
}
}
}
};
int main()
{
srand(time(0));
StarSystem starsystem0(0);
return 0;
}
可能是我的问题,这里的构造函数是一个没有定义的简单声明:
class StarSystem
{
public:
StarSystem(); // <--- Undefined!
你声明了一个构造函数,但是没有定义在这个构造函数中实际发生了什么。
如果它是一个什么都不做的构造函数,则执行
StarSystem () {} // Defined.
// Nothing happens inside, but everything gets default-constructed!
作为旁注,当发布这些东西时,它有助于发布错误编号,并在错误发生的地方放置注释或某种指示符(因此我们可以在您的巨大代码团中看到它)。
编辑:需要注意的是,如果您根本不使用该构造函数,请删除它。
您认为因为没有调用SystemBody()
,所以不需要定义它。然而,你是间接调用它。
不要做
SystemBody() {};
建议。这不是你想要的。如果您不使用它,请将其完全删除。
你的类Star继承自SystemBody
。这意味着当一个新的Star
被构造时,SystemBody
的构造函数被调用。
这一行
Star(int systembodyindex, int starsystemindex)
{
实际上被编译为
Star(int systembodyindex, int starsystemindex) :
SystemBody() // Here
{
如果你自己不调用SystemBody
的默认构造函数,编译器会调用它。
如果你考虑一下,当你创建一个新的Star
时,你需要以某种方式初始化SystemBody
。你可以显式地像
Star(int systembodyindex, int starsystemindex) :
SystemBody(systembodyindex) // Here
{
您定义了许多默认构造函数,但没有实现它们。而不是
StarSystem(); // <- it is OK if you implement this somewhere but you didn't
写StarSystem(){}
^^ this is empty implementation