Object Oriented Concepts Practice Problems

Object Oriented Concepts Practice Problems

Rational numbers contain an integer numerator and denominator. Write the code to implement a class named Rational which stores two private ints (numer and denom) with the following methods:

  public Rational(int,int);  //constructor that sets the numer and denom
  public Rational(Rational); //copy constructor for a Rational object

  public void setNumer(int); //sets the numerator to the paramter value
  public int getNumer();     //returns the stored numerator
  public void setDenom(int); //sets the denominator to the paramter value
  public int getDenom();     //returns the stored denominator

  //return a new Rational object that contains the reciprocal of the object that invokes the method.
  public Rational reciprocal();

  //returns a new Rational object that contains the product of the two paramteres.
  public static Rational multiply(Rational a, Rational b);

Implement a class named Cat such that objects of that type will contain a name and a number of lives and the class will keep track of how many Cat objects were ever created. The class will also have the following methods:

  //returns the number of lives the object that invoked the method has left
  public int getLives();    

  //decreases the number of lives of the object that invoked the method
  //  and returns true if it has any left but returns false if it is out
  //  of lives according to the int it holds
  public boolean useLife();

  //returns the number of Cat objects ever created
  public static int getCatsEver();

  //returns a String of the form
  //   Cat cat_name has # lives left.
  //or
  //   Cat cat_name has passed away.
  //depending on whether or not the number of lives has gone negative
  public String toString();