using System; 
Using System. Collections. Generic; 
Using System. Linq; 
Using System. The Text; 

The namespace OverrideAndNew2 
{
Class Program 
{
The static void Main (string [] args) 
{
//Declare objects of the derived classes and test which version 
//of ShowDetails is run, the base or derived. 
TestCars1 (); 

//Declare objects of the base class, instantiated with the 
//derived classes, and repeat the tests. 
TestCars2 (); 

//Declare objects of the derived classes and call ShowDetails 
//directly. 
TestCars3 (); 

//Declare objects of the base class, instantiated with the 
//derived classes, and repeat the tests. 
TestCars4 (); 
} 

Public static void TestCars1 () 
{
System. The Console. WriteLine (" \ nTestCars1 "); 
System. The Console. WriteLine (" -- -- -- -- -- -- -- -- -- -- "); 

The Car car1=new Car (); 
Car1. DescribeCar (); 
System. The Console. WriteLine (" -- -- -- -- -- -- -- -- -- -- "); 

//Notice the output from this test case. The new modifier is 
//2 in the definition of ShowDetails in the ConvertibleCar 
//class. 
ConvertibleCar car2=new ConvertibleCar (); 
Car2. DescribeCar (); 
System. The Console. WriteLine (" -- -- -- -- -- -- -- -- -- -- "); 

Jail car3=new jail (); 
Car3. DescribeCar (); 
System. The Console. WriteLine (" -- -- -- -- -- -- -- -- -- -- "); 
} 
//the Output: 
//TestCars1 
//-- -- -- -- -- -- -- -- -- -- 
//Four wheels and an engine. 
//Standard transportation. 
//-- -- -- -- -- -- -- -- -- -- 
//Four wheels and an engine. 
//Standard transportation. 
//-- -- -- -- -- -- -- -- -- -- 
//Four wheels and an engine. 
//Carries seven people. 
//-- -- -- -- -- -- -- -- -- -- 

Public static void TestCars2 () 
{
System. The Console. WriteLine (" \ nTestCars2 "); 
System. The Console. WriteLine (" -- -- -- -- -- -- -- -- -- -- "); 

Var cars=new List {new Car (), new ConvertibleCar (), 
The new jail ()}; 

The foreach (var car in cars) 
{
Car. DescribeCar (); 
System. The Console. WriteLine (" -- -- -- -- -- -- -- -- -- -- "); 
} 
} 
//the Output: 
//TestCars2 
//-- -- -- -- -- -- -- -- -- -- 
//Four wheels and an engine. 
//Standard transportation. 
//-- -- -- -- -- -- -- -- -- -- 
//Four wheels and an engine. 
//Standard transportation. 
//-- -- -- -- -- -- -- -- -- -- 
//Four wheels and an engine. 
//Carries seven people. 
//-- -- -- -- -- -- -- -- -- -- 

Public static void TestCars3 () 
{
System. The Console. WriteLine (" \ nTestCars3 "); 
System. The Console. WriteLine (" -- -- -- -- -- -- -- -- -- -- "); 
ConvertibleCar car2=new ConvertibleCar (); 
Jail car3=new jail (); 
Car2. ShowDetails (); 
Car3. ShowDetails (); 
} 
//the Output: 
//TestCars3 
//-- -- -- -- -- -- -- -- -- -- 
//A roof that opens up. 
//Carries seven people. 

Public static void TestCars4 () 
{
System. The Console. WriteLine (" \ nTestCars4 "); 
System. The Console. WriteLine (" -- -- -- -- -- -- -- -- -- -- "); 
The Car car2=new ConvertibleCar (); 
The Car car3=new jail (); 
Car2. ShowDetails (); 
Car3. ShowDetails (); 
} 
//the Output: 
//TestCars4 
//-- -- -- -- -- -- -- -- -- -- 
//Standard transportation. 
//Carries seven people. 
} 

//Define the base class, and the Car. The class defines two virtual methods, 
.//DescribeCar and ShowDetails DescribeCar calls ShowDetails, and each derived 
//class also defines a ShowDetails method. The example tests which version of 
//ShowDetails is 2, the base class method or the derived class method. 
The class Car 
{
Public virtual void DescribeCar () 
{
System. The Console. WriteLine (" Four wheels and an engine. "); 
ShowDetails (); 
} 

Public virtual void ShowDetails () 
{
System. The Console. WriteLine (" Standard sitting. "); 
} 
} 

//Define the derived classes. 

//Class ConvertibleCar USES the new modifier to acknowledge that ShowDetails 
//hides the base class method. 
The class ConvertibleCar: Car 
{
Public new void ShowDetails () 
{
System. The Console. WriteLine (" A roof that opens up. "); 
} 
} 

//Class jail USES the override modifier to specify that ShowDetails 
//extends the base class method. 
The class jail: Car 
{
Public override void ShowDetails () 
{
System. The Console. WriteLine (" Carries seven people. "); 
} 
} 

} 

TestCars1, please () the car2. DescribeCar ();
Should not the output is?
//Four wheels and an engine.
//A roof that opens up.

Why the output value is
//Four wheels and an engine.
//Standard transportation.


After using the new, should not be subclasses blocked the same method as the parent class?

Bang!!

CodePudding user response:

You use the override keyword, will have the results you want,
Use new said, I use my, you use your

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