看看这个错误'complex' : use of class template requires template argument list

[jzp12]

原程序如下:
#include <iostream>
#include <complex>
using namespace std;

class Mycomplex : public complex
{
public:
Mycomplex():complex(0,0){}
Mycomplex()(double r,double i):complex(r,i){}
friend int operator > (Mycomplex& c1,Mycomplex& c2);
};

int operator >(Mycomplex&c1,Mycomplex& c2)
{
return abs(c1)>abs(c2);
}

template <class T>
T& Bigger (T& a,T& b)
{
return (a>b) ? a : b;
}

int main()
{
int i1 = 10, i2 = 20, i3;
double d1 = 1.1,d2 = 2.2 , d3;
Mycomplex c1(1,2),c2(3,4),c3;
i3 = Bigger(i1,i2);
d3 = Bigger(d1,d2);
c3 = Bigger(c1,c2);
return 0;
}

编译错误如下:
E:\C++Language\WorkArea\Test070504\testmain.cpp(7) : error C2955: 'complex' : use of class template requires template argument list
c:\program files\microsoft visual studio\vc98\include\complex(267) : see declaration of 'complex'
E:\C++Language\WorkArea\Test070504\testmain.cpp(7) : fatal error C1903: unable to recover from previous error(s); stopping compilation

[lightnut]

1
std::complex是个模板类!!

class Mycomplex : public complex
====>
class Mycomplex : public complex<double>

2.

Mycomplex()(double r,double i):complex(r,i){}
====>
Mycomplex(double r,double i):complex(r,i){}

3.
friend int operator > (Mycomplex& c1,Mycomplex& c2);
===>
friend bool operator > (Mycomplex& c1,Mycomplex& c2);

[believefym]

use of class template requires template argument list
编译信息说得挺明白的，模板类的使用需要模板参数list

[linquanjushi]

谢谢高手能给一个完整的例子,我在用模板时也出现了问题,我自己设计了一个模板,但也出现了一楼那样的错误.

[xiaofang3100]

你的实现函数是不是要加个类作用域:: 你的函数是在类外实现的呀

[hityct1]

#include "stdafx.h"
#include <iostream> 
#include <complex> 
using namespace std; 

class Mycomplex:public complex<double>
{
public: 
	Mycomplex():complex<double>(0.0,0.0)
	{} 

	Mycomplex(double r,double i):complex<double>(r,i)
	{} 

	friend bool operator >(Mycomplex& c1,Mycomplex& c2) 
	{ 
		return   abs(c1)> abs(c2); 
	} 
}; 


template<class T> 
T Bigger (T& a,T& b) 
{ 
	return (a> b)?a:b; 
} 

int main() 
{ 
int   i1 = 10, i2 = 20, i3; 
double d1 = 1.1,d2 = 2.2, d3; 
Mycomplex   c1(1,2),c2(3,4),c3; 
i3   =   Bigger(i1,i2); 
cout<<i3<<endl;
d3   =   Bigger(d1,d2); 
cout<<d3<<endl;
c3   =   Bigger(c1,c2); 
cout<<c3<<endl;

return   0; 
} 

[jxqiong]

解释的挺好的，可是我的问题类型不大一样哦。

[sunnyes2008]

加我QQ:495711824我告诉你

[sunnyes2008]

定义对象时要把类型写上。

[禾火山]

怎么解决的呢？

[tenjingou]

举个例子，希望对你有帮助！
template <class Elem>
class dddd{};

dddd a; // 错误！！

正确的做法是：

dddd <int> a;

dddd是类模板名，而不是一个具体的类，类模板中的类型 Elem并不是一个实际类型，只是一个虚拟的类型，无法用它去定义类的对象。必须用实际类型名去取代虚拟的类型。