Question

How would you declare an interface named Sports that has the following (show them in your answer as well): A method called jump that has no parameters and does not return anything. A method called throw that has one parameter called distance and is an integer and does not return anything. 2) [5 pts] Assuming the interface exist from 1) above. Give me the class header for a class named Football that would use this interface. 3) [5 pts] Assuming a parent class called GrandParents exist. How would you create a child class called GrandChild that would be a direct child of the class GrandParents

Answer 1

Answer:

See explanation

Explanation:

An interface is declared as follows:

interface interface_name{          

   member fields

   methods  }  

So the Sports interface is declared as:

interface Sports{   }  

You can also write its as:

public interface Sports { }

Now this interface has a method jump that has no parameters and does not return anything. So it is defined as:

void jump();

You can also write it as:

public void jump();

Notice that it has a void keyword which means it does not return anything and empty round brackets show that it has no parameters. Lets add this to the Sports interface:

interface Sports{  

void jump();   }    

You can write it as:

public interface Sports {

  public void void jump();  }

Next, this Sports interface has a method throw that has one parameter called distance and is an integer and does not return anything. So it is defined as:

throw(int distance);

You can also write it as:

  public void throw(int distance)

Notice that this function has a void return type and one int type parameter distance. Now lets add this to Sports interface:

interface Sports{        

   void jump();  

   void throw(int distance);   }

This can also be written as:

public interface Sports {

 public  void jump();  

   public void throw(int distance); }

Next, the class header for a class named Football that would use this interface is as follows:

class Football implements Sports{  }

You can use the methods of Sports in Football too. So the complete interface with class Football becomes:

interface Sports{  

void jump();  

void throw(int distance);

}  

class Football implements Sports{  

public void print(){

}  

public void throw(int distance) {

}

Next we have a parent class called GrandParents. So child class called GrandChild that would be a direct child of the class GrandParents is:

class GrandChild extends GrandParents {   }

Basic syntax of a parent class and its child class is:

class child_class_name extends parent_class_name

{  

  //member fields and methods

}