Assignment 4

A fraction practice program.

Part 1:
You are going to create an equation class, for equations with Rationals.  It will look like
 

enum Operation {plus, minus, mult, divide};

class Equation {

public:

Equation( Rational f, Operation op, Rational s);  //f op s = answer

Equation();  //create some valid default Equation

bool set(Rational f, Operation oper, Rational s);  //returns false if there is a problem with the data

istream & read(istream & in);  //Reads an equation in the form Rational sym Rational

                                             // where sym is + - * or /

ostream & print(ostream & out); //Print the equation

static void setFormat(bool ); // true = with answer, false = no answer

Rational getFirstTerm();  // returns the first Rational

Rational getSecondTerm(); // returns the second Rational

Rational getAnswer(); // returns the answer

char getOperation();// returns the symbol + - * or /

private:

Rational first;

Rational second;

Operation op;

Rational answer;

static bool withAnswer;  //true, output should show answer.

static char theOps[4]; //set to +, -, *, /

        };

The set function, the alternate constructor, and ... should set the value of answer.
You should use the Rational class, not repeat the code that you used there.
(I will put up, next week,  a version of the Rational class that you may use, or you may use your own.  You may modify the Rational class, but only to improve it, not to have it do work that should be done by the Equation class.  In particular, you will need to modify the input and output functions for Rational to use files.)
The two static data members should have their initial values set in the cpp file, as if they were global variables.

The output operator prints an equation with or without the answer.
For example, if we already have the rationals
   a = 2/3  b=1/5
then we want

   Equation e;

   e.set(a,plus,b);

   e.setFormat(true);

   e.print(cout);

If we then have

   e.setFormat(false);

   e.print(cout);

Make sure your Equation class in running well by writing a test stub.  Be sure you try all different kinds of equations.  Also, remember that all functions should be short, not longer than a page, so complex tasks should be broken down further.  If you need other functions to help, you may declare them in the class either as public if they will be useful to others, or a s private if you (and the member functions) are only one who will be using them.

2.  Now that you have the working class, you should use it as part of an interactive program for giving students practice with fractions.  There will be a file, fractiondata.txt, consisting of many problems of the form
    Rational operation Rational
for example
   3/5 + 9/2
   0/5 + 8/3
The first item in the file will be the number of problems in the file.
Sample file.

Your program should

• read the file into an array of Equations
• ask the user for their id number (an integer)
• ask them how many problems they want (should not be greater than the number in the file)
• shuffle the problems
• display the problems, without answer, one at a time, waiting for the user to enter an answer.
• if the user answers correctly, say so and go on to the next problem.
• if the user answers incorrectly,  print out the Equation with the correct answer, return the problem to the list of questions to be asked (if possible), and go on to the next problem.
• You should keep track of the number of correct and incorrect answers.
• In a file, teacher_records.txt, you should print the student's ID number, the number correct, and the number wrong.
• In a file, morepractice.txt, you should print the student's ID number, and a list of all the problems he got wrong, without the answers.  In a file, practiceanswers.txt, you should print the student's ID number, the same problems, but with answers.
• When the student is done with her practice, she should be given the option of another practice (using the same id),  handing the program over to another student with a different id, or quitting altogether.