Identifying Objects and Creating Software Objects

Learning Objective

1. Identifying Real world Objects
2. Creating Software Objects using class.
3. Implement state and behavior of software objects.

Instructional Activities

Reference Reading:

• What is an Object
• Object Oriented Programming
• CPlusPlus -> Classes Basic tutorial

Problem Sets

Problem Set A

1. Identify 5 objects in real world

1. List the state of these objects
2. List the behavior of these objects
3. Note: Your list of objects should be unique from the entire class. Otherwise you would be give zero marks for the whole of this module

Problem Set B

1. Classes and Objects: Using the following class create an object for it in the main program

   class Integer {
     private:
         int integer;
     public:
         void readInteger();
         void printMessage();
  };

 void Integer::readInteger() {
      cout<<"enter the value of N";
       cin>>N;
 }
 void Integer::printMessage() {
              for (int i = 0 ; i < N ; i++) {
                  cout<<Hello<<endl;
              }
  }

1. Create a object called “intobj” for the class “Integer” in the main program
   • Call intobj.readInteger() and intobj.printMessage() from the main program
   • Add another member function called int addInteger(int no) to the class Integer.
   • The function addInteger() returns the sum of the value of “N + no”.
   • Call intobj.addInteger() from the main program
2. Create a class called "class Circle { };"
   • Add members function to readRadius
   • Add a member function to displayArea
   • Create an object for the class Circle
   • Call the member functions readRadius() and displayArea() from the main program.

2. Create the class called 'Math'.

  class Math{
  private:
    int ival
  public:
     int sum(int x, int y);
 };

1. Create a class called “Math”
   • Complete the member function int sum(int x, int y);
     • return the sum of x and y;
   • Write a main program which creates an object say “m” for the class “Math”
     • From the main program read two integers i1, i2.
     • Call the member function “total = m.sum(i1, i2)” to get the sum of i1 + i2
2. Accessing private member in member functions:
   • Modify the member functions so that sum() stores the output in ival.
   • ival = x + y; return ival;

Problem Set C

1. Create a class called State() with the following member functions

• readDistricts(); //read N = no of districts, dynamically allocated memory for N strings, read each district name from the stdin.
• printDistricts(); //print the district names on the standard output (display-screen);
• Use dynamic allocation of strings in the classes is compulsory:

1. Create an object for the class State in the main program
2. Call read_districts() and printDistricts() from the main program

2. Create class called Interest

1. Create class called Interest with the following attributes and behavior
   • Attributes
     • Principle Amount
     • Number of Years
     • Rate of Interest
   • Behavior
     • readPrincipleAmount();
     • readNoOfYears();
     • readInterestRatePY();
     • calcuateSimpleInterest();
     • calculateCompoundInterest();
2. Create an object for the class Interest in the main program
3. call member functions, read* to read principle amount, no. of years and interest rate
4. call calcuateSimpleInterest() and calculateCompoundInterest() to display the amount+interest separately.

3. Create class for 3 Objects identified in Problem Set A 1
Create 3 classes with state and behavior identified.
Create an object for the 3 classes in the main program and test them.