The interface cannot contain fields, constructors, destructor, static members, or constants. Otherwise, errors may occur.

The interface cannot contain fields, constructors, destructor, static members, or constants. Otherwise, errors may occur.

Define an excuse, the interface encapsulates the length and width of the rectangle, and also contains a custom method to calculate the area of the rectangle. Define a class, inherit from this interface, and implement custom methods in this class.

1 using System; 2 using System. collections. generic; 3 using System. linq; 4 using System. text; 5 6 namespace Test06 7 {8 interface ImyInterface 9 {10 /// <summary> 11 /// 12 // </summary> 13 int Width14 {15 get; 16 set; 17} 18 /// <summary> 19 /// width 20 /// </summary> 21 int Height22 {23 get; 24 set; 25} 26 /// <summary> 27 // calculate the rectangle Area 28 /// </summary> 29 int Area (); /// // int Area (int Width, int Height); 30} 31 class Program: ImyInterface // inherited from interface 32 {33 private int width = 0; 34 private int height = 0; 35 // <summary> 36 // length 37 /// </summary> 38 public int Width39 {40 get41 {42 return width; 43} 44 set45 {46 width = value; 47} 48} 49 // <summary> 50 // width 51 // </summary> 52 public int Height53 {54 get55 {56 return height; 57} 58 set59 {60 height = value; 61} 62} 63 // <summary> 64 // calculate the rectangle Area 65 // </summary> 66 public int Area (int Width, int Height) 67 {68 return Width * Height; 69} 70 static void Main (string [] args) 71 {72 Program program = new Program (); // instantiate the Program Class Object 73 ImyInterface imyinterface = program; // use the derived class Object Instantiation interface ImyInterface74 imyinterface. width = 5; // assign 75 imyinterface to the Width attribute in the derived class. height = 3; // assign a value to the Height attribute in the derived class 76 Console. writeLine ("the area of the rectangle is:" + imyinterface. area (3, 5); 77} 78} 79}

The following is correct:

1 using System; 2 using System. collections. generic; 3 using System. linq; 4 using System. text; 5 6 namespace Test06 7 {8 interface ImyInterface 9 {10 /// <summary> 11 /// 12 // </summary> 13 int Width14 {15 get; 16 set; 17} 18 /// <summary> 19 /// width 20 /// </summary> 21 int Height22 {23 get; 24 set; 25} 26 // <summary> 27 // calculate the rectangle Area 28 // </summary> 29 int Area (); 30} 31 class Program: imyInterface // inherited from interface 32 {33 int width = 0; 34 int height = 0; 35 /// <summary> 36 /// length 37 /// </summary> 38 public int Width39 {40 get41 {42 return width; 43} 44 set45 {46 width = value; 47} 48} 49 // <summary> 50 // width 51 // </summary> 52 public int Height53 {54 get55 {56 return height; 57} 58 set59 {60 height = value; 61} 62} 63 // <summary> 64 // calculate the rectangle Area 65 // </summary> 66 public int Area () 67 {68 return Width * Height; 69} 70 static void Main (string [] args) 71 {72 Program program = new Program (); // instantiate the Program Class Object 73 ImyInterface imyinterface = program; // use the Object Instantiation interface of the derived class ImyInterface74 imyinterface. width = 5; // assign 75 imyinterface to the Width attribute in the derived class. height = 3; // assign a value to the Height attribute in the derived class 76 Console. writeLine ("the area of the rectangle is:" + imyinterface. area (); 77} 78} 79}

The key error point of this question is: The method declaration form in the interface should be consistent with the method definition form in the interface implementation; otherwise, an error will occur:"

Error 1 the "Area" method does not have any overload using "2" Parameters"