Question

Info: The next question related to the Exam class whose definition (.h file) is shown below. This Exam class represents a certain student’s test score.

       #include <string>

       namespace cs31 {

        class Exam { 

          public:
             Exam ( std::string student, int score = 90 );   
             bool equal( const Exam & e1,  const Exam & e2 ) const;
             int         getScore() const;     
             std::string getStudent() const;   

         private:

             std::string  mName;   // Exam’s Student name
             int mScore;           // Exam’s Student Score

         };

       }

1a) Suppose we decide to create a setter named Exam::setScore( int score ) to update the matching appropriate data member. What will its implementation look like in the matching .cpp file?

Select one:

a. void Exam::setScore( int score ) const
{
mScore = score;
}

b. int Exam::setScore( ) const
{
return( mScore );
}

c. void Exam::setScore( int score )
{
mScore = score;
}

d. void setScore( int score )
{
mScore = score;
}

1b) You are working with a partner to build an online grading system that works with the class Exam shown above. Your partner has added a new method to the Exam class defined as:            void Exam::bar( int i ) const;
What do you know from this declaration?

Select one:

a. The Exam instance you use to call this method bar maybe changed

b. A class method cannot be marked const, so this declaration will break the Exam class

c. The Exam instance you use to call this method bar will not be changed, no matter what happens

d. None of the above choices are correct

1c)

You are working with a partner to build an online grading system that works with the class Exam shown above. Your partner has defined the function signature:     void foo( Exam & e )     
What do you know from this declaration?

Select one:

a. C++ will make a copy of the exam instance you pass to this function foo and use it inside this function foo

b. None of the above choices are correct

c. The Exam instance you pass to this function foo maybe changed by the function

d. The Exam instance you pass to this function foo will not be changed, no matter what happens

Answer 1

1. a)
c. void Exam::setScore( int score )
{
mScore = score;
}

The function cannot be a const since it is changing the instance variable, so option a and b are wrong. Option c is correct because the implementation of a function must have the class mentioned in the .cpp file

1. b)
c. The Exam instance you use to call this method bar will not be changed, no matter what happens

A function with the keyword const cannot the object that is used to call it, so option c is the correct option.

1. c)
c. The Exam instance you pass to this function foo maybe changed by the function

The instance of Exam e is passed by reference using the symbol &, which indicates that the function may change the instance inside this function and it wants the change to reflect outside the function too.