#include <iostream> #include <cmath> using namespace std; class figure { protected: double He; double Wi; public: figure(double H, double W); }; figure::figure(double H, double W) { cin >> W >> H; cout << W << " ### " << H << endl; He = H; Wi = W; } class rectangle :public figure { public: rectangle(double H, double W) :figure(H, W) { }; void area(); void display(); }; void rectangle::display() { cout << "W: " << Wi << "H: " << He << endl; } void rectangle::area() { cout << "S= " << Wi * He << endl; } class triangle :public figure { public: triangle(double H, double W) :figure(H, W) { }; void area(); void display(); }; void triangle::display() { cout << "W: " << Wi << "H: " << He << endl; } void triangle::area() { double n = 0.5; cout << n * Wi * He << endl; } int main() { double width, height; cin >> width >> height; triangle tri(width, height); rectangle rect(width, height); tri.display(); cout << ". The area is "; cout << tri.area() << endl; rect.display(); cout << ". The area is " << rect.area() << endl; return 0; }

这段代码中存在一些问题。具体问题如下：

1. `#include` 库文件时应该每个文件一行，而不是写在同一行。
2. 类 `figure` 的构造函数中的输入语句应该放在 `main` 函数中，而不是在构造函数中。
3. 类 `triangle` 和类 `rectangle` 中的 `area` 函数应该返回一个值，而不是 `void` 类型。
4. 在 `main` 函数中，输出 `tri.area()` 和 `rect.area()` 的语句应该分别放在 `tri.area()` 和 `rect.area()` 的函数调用后面。

下面是修改后的代码：

#include <iostream> 
#include <cmath>  

using namespace std;  

class figure { 
protected: 	
    double He; 	
    double Wi; 
public: 	
    figure(double H, double W) : He(H), Wi(W) {} 
}; 

class rectangle : public figure { 
public: 	
    rectangle(double H, double W) : figure(H, W) {} 	
    double area(); 	
    void display(); 
}; 

void rectangle::display() { 	
    cout << "W: " << Wi << "H: " << He << endl; 
} 

double rectangle::area() { 	
    return Wi * He; 
} 

class triangle : public figure {  
public: 	
    triangle(double H, double W) : figure(H, W) {}  	
    double area(); 	
    void display(); 
}; 

void triangle::display() { 	
    cout << "W: " << Wi << "H: " << He << endl; 
} 

double triangle::area() { 	
    double n = 0.5; 	
    return n * Wi * He; 
} 

int main() { 	
    double width, height; 	
    cin >> width >> height; 

    triangle tri(height, width); 	
    rectangle rect(height, width); 	

    tri.display(); 	
    cout << ". The area is " << tri.area() << endl; 
    rect.display(); 	
    cout << ". The area is " << rect.area() << endl; 

    return 0; 
}