Erreur: doit avoir un corps car il n'est pas marqué abstrait extern ou partiel

Question

J'ai le code ci-dessous et je continue d'obtenir l'erreur doit avoir un corps car il n'est pas marqué abstrait extern ou partiel.

public interface Shape{ 
    int GetArea(); 
} 
public class shape:Shape{ 
    int height; 
    int width; 
    int radius; 
    int GetArea(); 

} 
class Rectangle :Shape{ 
    int height; 
    int width; 
    Rectangle(int height,int width){ 
     this.height = height; 
     this.width = width; 
    } 
    int GetArea(){ 
     int area = height*width; 
     return area; 
    } 
} 

Answer 1

Vous devriez implémenter l'interface Shape comme celui-ci (ne pas oublier le mot-clé public dans la mise en œuvre):

public class shape : Shape 
{ 
    public int GetArea() 
    { 
     return 0;//Return an int value 
    } 

} 
class Rectangle : Shape 
{ 
    public int GetArea() 
    { 
     int area = height * width; 
     return area; 
    } 
} 

Answer 2

Essayez ceci:

//1. Change interface name from Shape to IShape; to 
// be in line with standards and to avoid being 
// too close to your original class name, `shape` 

public interface IShape { 
    int GetArea(); 
} 

//2. Change your class from `shape` to `Shape`; again 
// to be in line with standards. Also given we 
// changed to IShape above, amend the interface name 
// here also. 

//3. Add keyword `abstract`. Since we don't have a body 
// (i.e. a definition) for the GetArea method, we can't 
// instantiate it, so it has to be abstract 
public abstract class Shape:IShape { 
    //4. Make our fields protected; since we can't instantiate 
    // this class there's no point having them here unless 
    // they're made visible to any classes which inherit from 
    // this class. 
    protected int height; 
    protected int width; 
    protected int radius; 
    //5. Since GetArea is required (to implement interface IShape) 
    // but has no body defined, make it abstract. 
    public abstract int GetArea(); 
} 

//6. We changed the class from `shape` to `Shape`, so change here also. 
//7. You probably also want to make this class & it's constructor public 
// though I can't guarentee that (hence commented out) 
/* public */ class Rectangle : Shape { 
    /* public */ Rectangle(int height,int width){ 
     this.height = height; 
     this.width = width; 
    } 
    //8. To implement the interface this method needs to be made public. 
    //9. You also need to use the `override` keyword to say that this 
    // replaces the abstract method on the base class (`Shape`) 
    public override int GetArea() { 
     int area = height * width; 
     return area; 
    } 
}