quiz.cpp

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#include <iostream>
#include <string>
using namespace std;
#include "mathquest.h"
#include "prompt.h"

// quiz program for illustrating class design and implementation

class Student
{
  public:
    Student(const string& name);   // student has a name

    int    Score() const;          // # correct
    string Name()  const;          // name of student
    
    bool RespondTo(Question & q);  // answer a question, update stats
    
  private:
    
    string myName;        // my name
    int    myCorrect;     // my # correct responses
};

Student::Student(const string& name)
  : myName(name),
    myCorrect(0)
{
    // initializer list does the work
}

bool Student::RespondTo(Question & q)
// postcondition: q is asked, state updated to reflect responses
//                return true iff question answered correctly
{
    string answer;
    q.Ask();
    cin >> answer;
    
    if (q.IsCorrect(answer))
    {   myCorrect++;
        cout << "yes, that's correct" << endl;
        return true;
    }
    else
    {   cout << "no, that's not correct" << endl;
        return false;
    }
}

int Student::Score() const
// postcondition: returns # correct
{
    return myCorrect;
}

string Student::Name() const
// postcondition: returns name of student
{
    return myName;
}

class Quiz
{
  public:
    Quiz();  
    void GiveQuestionTo(Student & s); // ask student a question
    
  private:
    
    Question myQuestion; // question generator
};

Quiz::Quiz()
  : myQuestion()
{
  // nothing to do here
}

void Quiz::GiveQuestionTo(Student & s)
// postcondition: student s asked a question
{
    cout << endl << "Ok, " << s.Name() << " it's your turn" << endl;
    cout << "type answer after question " << endl;

    myQuestion.Create();
    if (! s.RespondTo(myQuestion))
    {   cout << "try one more time" << endl;
        if (! s.RespondTo(myQuestion))
        {    cout << "correct answer is " << myQuestion.Answer() << endl;
        }
    }
}

int main()
{
    Student owen("Owen");
    Student susan("Susan");
    Quiz q;
    int qNum = PromptRange("how many questions: ",1,5);
    int k;
    for(k=0; k < qNum; k++)
    {   q.GiveQuestionTo(owen);
        q.GiveQuestionTo(susan);
    }
    cout << owen.Name()  << " score:\t" << owen.Score() 
         << " out of " << qNum
         << " = " << double(owen.Score())/qNum * 100 << "%" << endl;
    cout << susan.Name() << " score:\t" << susan.Score() 
         << " out of " << qNum    
         << " = " << double(susan.Score())/qNum * 100 << "%" << endl;
    
    return 0;
}