Question

1. (20 pts) Inside a method main, we see code like:

     Airplane.foo3(34.6);

From this, reconstruct the header of method foo3 (which belongs to class Airplane); make appropriate assumptions if necessary. Write the method header as your answer.

              

2. (20 pts) Inside method main, we see code like:

Airplane a = new Airplane();

int n = a.foo4(“Hello”);

From this, reconstruct the header of method foo4 (which belongs to class Airplane)

Write the method header as your answer.

3. (40 pts) You coded the following class:

You coded the following definition for the class Grade:

public class Grade

{

private char letterGrade;

public Grade(char 1g)

{

     letterGrade = lg;

   }

public String toString() //line 10

   {                                   //line 11

       return letterGrade;    //line 12

}                                    //line 13

}

When you compile, you get the following message:

Grade.java:12: incompatible types

return letterGrade;

           ^

found : char

required: String

1 error

Explain what the problem is and how to fix it.

Answer 1

1.

public static void foo3(double num);

2.

public int foo4(String str);

3.

The error occurs because letterGrade is of type char, and the return type of toString() method is String.

To overcome this error, we can return

return letterGrade + "";