大家好，我是新手。今天在C++教程上原封的敲了一段程序，在VC++上。程序如下：
#include<iostream.h>
class figure{
protected:
double x,y;
public:
firgure(double a,double b)
{x=a;y=b;}
virtual void show_area()
{cout<<"No area computation defined";
cout<<"for this class.\n";
}
};
class triangle: public figure
{public:
trigngle(double a,double b):figure(a,b)
{};
void show_area()
{cout<<"Triangle with height"<<x;
cout<<"and base"<<y<<"has an area of";
cout<<x*y*0.5<<endl;}
};
class square:public figure{
public:
square(double a,double b):figure(a,b)
{};
void show_area()
{cout<<"Square with dimension"<<x;
cout<<"*"<<y<<"has an area of";
cout<<x*y<<endl;
}
};
class circle:public figure{
public:
circle(double a):figure(a,a)
{};
void show_area()
{cout <<"Circle with radius"<<x;
cout<<"has an area of";
cout<<x*x*3.1416<<endl;
}
};
main()
{figure *p;
triangle t(10.0,6.0);
square s(10.0,6.0);
circle c(10.0);
p=&t;
p->show_area();
p=&s;
p->show_area();
p=&c;
p->show_area();
return 0;
}
这个程序的功能是求三角形，圆形和矩形的面积。可是我按F5后，出现了如下的提示
--------------------Configuration: my_test - Win32 Debug--------------------
Compiling...
my_test.cpp
Linking...
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/my_test.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

my_test.exe - 2 error(s), 0 warning(s)
由于我是新手。我想知道我的上面的程序有问题吗。还是出现了什么语法错误。我用的教程是清华出版社出版的C++教程。运行环境是VC++，希望哪位能帮我。感激不胜！

#include<iostream.h>
class figure{
protected:
double x,y;
public:
figure(double a,double b)
{x=a;y=b;}
virtual void show_area()
{cout<<"No area computation defined";
cout<<"for this class.\n";
}
};
class triangle: public figure
{public:
trigngle(double a,double b):figure(a,b)
{};
void show_area()
{cout<<"Triangle with height"<<x;
cout<<"and base"<<y<<"has an area of";
cout<<x*y*0.5<<endl;}
};
class square:public figure{
public:
square(double a,double b):figure(a,b)
{};
void show_area()
{cout<<"Square with dimension"<<x;
cout<<"*"<<y<<"has an area of";
cout<<x*y<<endl;
}
};
class circle:public figure{
public:
circle(double a):figure(a,a)
{};
void show_area()
{cout <<"Circle with radius"<<x;
cout<<"has an area of";
cout<<x*x*3.1416<<endl;
}
};
main()
{figure *p;
triangle t(10.0,6.0);
square s(10.0,6.0);
circle c(10.0);
p=&t;
p->show_area();
p=&s;
p->show_area();
p=&c;
p->show_area();
return 0;
}
回复下。我首先发生了问题。呵呵。就是figure类中的构造函数多写了一个r.现将修改后的程序送上。谢谢！

晕。又发现问题了。。。。在triangle类中又写错构造函数了。。。。。谢谢斑竹大哥，别砍死我。。#include<iostream.h>
class figure{
protected:
double x,y;
public:
figure(double a,double b)
{x=a;y=b;}
virtual void show_area()
{cout<<"No area computation defined";
cout<<"for this class.\n";
}
};
class triangle: public figure
{public:
triangle(double a,double b):figure(a,b)
{};
void show_area()
{cout<<"Triangle with height"<<x;
cout<<"and base"<<y<<"has an area of";
cout<<x*y*0.5<<endl;}
};
class square:public figure{
public:
square(double a,double b):figure(a,b)
{};
void show_area()
{cout<<"Square with dimension"<<x;
cout<<"*"<<y<<"has an area of";
cout<<x*y<<endl;
}
};
class circle:public figure{
public:
circle(double a):figure(a,a)
{};
void show_area()
{cout <<"Circle with radius"<<x;
cout<<"has an area of";
cout<<x*x*3.1416<<endl;
}
};
main()
{figure *p;
triangle t(10.0,6.0);
square s(10.0,6.0);
circle c(10.0);
p=&t;
p->show_area();
p=&s;
p->show_area();
p=&c;
p->show_area();
return 0;
}
最后这段程序应该是0 error和0warning

晕啊。可是F5运行后弹出一个黑色窗口就没有了。后来我在调试标签下发现了如下的提示：
aded 'C:\WINNT\system32\ntdll.dll', no matching symbolic information found.
Loaded 'C:\WINNT\system32\kernel32.dll', no matching symbolic information found.
The thread 0x854 has exited with code 0 (0x0).
The program 'C:\Program Files\Microsoft Visual Studio\VC98\ATL\Include\Debug\my_next_test.exe' has exited with code 0 (0x0).

请问这是怎么回事啊。我知道*.dll是动态连接库文件。是不是我的C++版本有问题？拜托，拜托了

我的没有错误．有危险！快跑呀！！啊啊！

楼上的前辈你说的是什么意思啊。能不能告诉我啊

你有听过谢廷锋的一首歌．．．来了，来了，Music"因为爱，所以爱，不懂．．．．．．＂；

拜托别卖关子了。等着救命呢

你按下"Ctrl+F5"保证没问题！！！我轻轻的来，轻轻的走．......