修改一段小代码

[chenShuyuNO1]

#include<iostream>
using namespace std;
class Rectangle
{
public :
Rectangle(double NewL,double NewW);
double Area();
private:
double Lenth;
double Width;
}
Rectangle::Rectangle(double NewL=0,double NewW=0)
{
Lenth=NewL;
Width=NewW;
}
double Rectangle::Area()
{
return Lenth*Width;
}
int main()
{
double Lenth;double Width;
cout<<"请输入矩形的长:";
cin>>Lenth;
cout<<"请输入矩形的宽:";
cin>>Width;
Rectangle mytangle(0, 0);
mytangle.Area();
cout<<"矩形的面积为:"<<mytangle.Area()<<endl;
return 0;
}我调试的时候总是出现'Rectangle::Rectangle' : error in function definition or declaration; function not called,这条语句帮忙修改一下.谢谢各位拉

[tangshuiling]

类定义少个分号！
{
}；

[weiyanno1]

#include <iostream>
using namespace std;
class Rectangle
{
public :
Rectangle(double NewL,double NewW);
double Area();
private:
double Lenth;
double Width;
};
Rectangle::Rectangle(double NewL,double NewW)
{
Lenth=NewL;
Width=NewW;
}
double Rectangle::Area()
{
return Lenth*Width;
}
int main()
{
double Lenth;double Width;
cout<<"请输入矩形的长:";
cin>>Lenth;
cout<<"请输入矩形的宽:";
cin>>Width;
Rectangle mytangle(Lenth, Width);
mytangle.Area();
cout<<"矩形的面积为:"<<mytangle.Area()<<endl;
return 0;
}

[weiyanno1]

#include <iostream> 
using namespace std; 
class Rectangle 
{ 
public : 
   Rectangle(double NewL,double NewW); 
   double Area(); 
private: 
   double Lenth; 
   double Width; 
}; 
Rectangle::Rectangle(double NewL,double NewW) 
{ 
   Lenth=NewL; 
   Width=NewW; 
} 
double Rectangle::Area() 
{ 
   return Lenth*Width; 
} 
int main() 
{ 
    double Lenth;double Width; 
    cout<<"请输入矩形的长:"; 
    cin>>Lenth; 
    cout<<"请输入矩形的宽:"; 
    cin>>Width; 
    Rectangle mytangle(Lenth, Width); 
    mytangle.Area(); 
    cout<<"矩形的面积为:"<<mytangle.Area()<<endl; 
    return 0; 
}

[太乙]

#include <iostream> 
using namespace std; 
class Rectangle 
{ 
public : 
	Rectangle(double NewL,double NewW); 
	double Area(); 
private: 
	double Lenth; 
	double Width; 
} ;
Rectangle::Rectangle(double NewL=0,double NewW=0) 
{ 
	Lenth=NewL; 
	Width=NewW; 
} 
double Rectangle::Area() 
{ 
	return Lenth*Width; 
} 
int main() 
{ 
	double Lenth;double Width; 
    cout <<"请输入矩形的长:"; 
	cin>>Lenth; 
	cout <<"请输入矩形的宽:"; 
	cin>>Width; 
	Rectangle mytangle(0, 0); 
	mytangle.Area(); 
	cout <<"矩形的面积为:" <<mytangle.Area() <<endl; 
	return 0; 
}

[zzq0406]

#include <iostream>
using namespace std;
class Rectangle
{
public :
Rectangle(double NewL=0,double NewW=0); //带默认值只能在类声明中使用
double Area();
private:
double Lenth;
double Width;
} ;
Rectangle::Rectangle(double NewL,double NewW)
{
Lenth=NewL;
Width=NewW;
}
double Rectangle::Area()
{
return Lenth*Width;
}
int main()
{
double Lenth;double Width;
cout <<"请输入矩形的长:";
cin>>Lenth;
cout <<"请输入矩形的宽:";
cin>>Width;
Rectangle mytangle(0, 0);
mytangle.Area();
cout <<"矩形的面积为:" <<mytangle.Area() <<endl;
return 0;
}
/////////////////////////////
1.带默认值只能在类声明中使用
2 .类后要带“；”。

[zzq0406]

#include <iostream>
using namespace std;
class Rectangle
{
public :
Rectangle(double NewL=0,double NewW=0); //带默认值只能在类声明中使用
double Area();
private:
double Lenth;
double Width;
} ;
Rectangle::Rectangle(double NewL,double NewW)
{
Lenth=NewL;
Width=NewW;
}
double Rectangle::Area()
{
return Lenth*Width;
}
int main()
{
double Lenth;double Width;
cout <<"请输入矩形的长:";
cin>>Lenth;
cout <<"请输入矩形的宽:";
cin>>Width;
Rectangle mytangle(0, 0);
mytangle.Area();
cout <<"矩形的面积为:" <<mytangle.Area() <<endl;
return 0;
}
/////////////////////////////
1.带默认值只能在类声明中使用
2 .类后要带“；”。

[jia_xiaoxin]

#include <iostream> 
using namespace std; 
class Rectangle 
{ 
public : 
	Rectangle(double NewL=0,double NewW=0); //只能在声明中使用默认参数
	double Area(); 
private: 
	double Lenth; 
	double Width; 
}; //少了;号
Rectangle::Rectangle(double NewL,double NewW) 
{ 
	Lenth=NewL; 
	Width=NewW; 
} 
double Rectangle::Area() 
{ 
	return Lenth*Width; 
} 
int main() 
{ 
	double Lenth;double Width; 
    cout <<"请输入矩形的长:"; 
	cin>>Lenth; 
	cout <<"请输入矩形的宽:"; 
	cin>>Width; 
	Rectangle mytangle(0, 0); 
	mytangle.Area(); 
	cout <<"矩形的面积为:" <<mytangle.Area() <<endl; 
	return 0; 
}

[cui22698]

楼上几位的做法是对的，
1、要记住在定义类或者结构结束时不要忘记“;”
2、Rectangle mytangle(0, 0)=》Rectangle mytangle(Lenth, Width);