21333

Today's Agenda:
1) Overloading normal method
2) Method chaining
3) Overloading operators
4) Brainstorming sesson on project milestone-1
==============================================
class ComplexNo{
  int real, img;
  public:
  //fill in the blacks so that your main works
  ComplexNo(){real=img=0;}
  ComplexNo(int x){
	real=x;
	cout<<"Enter img value: "; cin>>img;
  }
  ComplexNo(int x, int y){real=x; img=y;}
  void showCoplexNo(){
     cout<<real<<(img>=0?"+":"")<<img<<"i"<<endl;
  }
  void add(ComlexNo cn1, ComlexNo cn2, ComlexNo cn3){
     real = cn1.real + cn2.real + cn3.real;
     img = cn1.img + cn2.img + cn3.img;
  }
  ComlexNo add(ComplexNo cn2, ComplexNo cn3){
     ComplexNo temp;
     temp.real = real + cn2.real + cn3.real;
     temp.img = img + cn2.img + cn3.img;
     return temp;
  }
  ComlexNo& operator+(ComplexNo c){
     ComplexNo temp;
     temp.real = real + c.real;
     temp.img = img + c.img;
     return temp;
  }

};

int main(){
  ComplexNo c1, c2(10), c3(23,33), c4, c5, c6,c7;
  cout<<"set c1: "<<endl;
  cout<<"c1 before setting = "; c1.showComplexNo();
  c1.setComplexNo();
  c4.add(c1,c2,c3);
  //c5.add(c1,c2,c3,c4);
  c5 = c1.add(c2,c3);
  cout<<"c1 = "; c1.showComplexNo();
  cout<<"c2 = "; c2.showComplexNo();
  cout<<"c3 = "; c3.showComplexNo();
  cout<<"c4 = "; c4.showComplexNo();
  c6 = c1 + c2;   cout<<"c6 = "; c7.showComplexNo();
  c7 = c3+c4+c5; cout<<"c7 = "; c7.showComplexNo();
  return 0;
}
------------------
RUN:
Enter img value: 12
set c1:
c1 before setting = 0+0i
Enter real value: 4
Enter img value: -2
c1 = 4-2i
c2 = 10+12i
c3 = 23+33i
c4 = 37+43i
c5 = 37+43i
-----------------------------------
1		2		3
x	+	y	+	z
	3		+	3

c6 = c1 + c2 + c3 + c4 + c5;

operator function: special method
format:

returnType operator"theOperator"(pType p1,...){

}
returnType operator+(pType p1,...){

}
c3 = c1+c2; //c3 = c1.operator+(c2);
c4 = c1+c2+c3; //   c1.operator+(c2)
			temp.operator+(c3);
c4 = c1.operator+(c2).operator+(c3);
cout<<	getSum(x,y) + z;
--------------------
c9  = 5 + c2; //operator+(5,c2);

---------------

RT operator=(ClassType c){
   field1 = c.field1;
   field2 = c.field2;
   field3 = c.field3;
}
------------------------------
class Person{
   int noOfTaskCompleted;
   public:
   Person(){noOfTaskCompleted=0;}
   int getNoOfTaskCompleted(){ return noOfTaskCompleted;}
   //void buySnack(){
   Person buySnack(){
       cout<<"Snacks are bought.. :-)"<<endl;
       noOfTaskCompleted++;
       return *this;
   }
   //void arrangeLivingRomm(){
   Person arrangeLivingRomm(){
       cout<<"Living room is arranged.. :-("<<endl;
       noOfTaskCompleted++;
       return *this;
   }
   void serveSnack(){
       cout<<"Snack is served.. !!!!"<<endl;
       noOfTaskCompleted++;
   }
};

//RT callerIsAMethodRepresentingRabbi(){
int main(){
   Person roudru;
   roudru.buySnack();
   roudru.arrangeLivingRomm();
   roudru.serveSnack();
   //roudru.buySnack().arrangeLivingRoom().serveSnack();
   cout<<"No of task completed is: "
	<<roudru.getNoOfTaskCompleted()<<endl;
}




----------------------
Student asif;
Student* ptr = &asif;

asif.id; //legal
ptr.id; //illegal
ptr->id; //legal
(*ptr).id; //legal


==================
Lab exercise:
--------------



class Book{
  //field: isbnNo, title, price;
  //string *autherPtr; int authorNo;
public:
  //write default constructor [2 marks]
  //add other necessary member functions...
  //declare necessary friend functions...
};

//need to overload >> operator to allow chaining
//Should ask info for all the fields from user

//need to overload << operator to allow chaining
//Should display all the fields of the object iff
//the default values are replaced with user input

int main(){
  int n, i; cin>>n;
  Book bookArr[n]; //an array of Book objects

  int noOfAuthors = populateBooks(bookArr, n);
  //write this global function
  //This function will replace the default values (set by constructor) of
  //n Books by using cin>>BookObject format in a loop. Finally it returns
  //total number of authors of all books of the array.

  cout<<”No of authors of all books is: “<<noOfAuthors<<endl;
  cout << “Detail of the books are: “ << endl;
  for(i=0; i<n ;i++) cout << bookArr[i] << endl;
  int index = getBookIndexWithLowestPrice(bookArr, n); [2 marks]
  int x; cin>>x;

  if(bookArr[index]<500.0) bookArr[index] += x;
  //bookArr[index] is a book and if it’s
  //price is <500 taka, then += will increase
  //the book’s price by x%. Write necessary
  //operator functions ( < , += )

  Book b1, b2, b3, b4; cin>>b1>>b2>>b3>>b4;

  //overload ‘+’ operator twice.
  //‘+’ means adding price, not books
  cout<<( (b1+b2+b3+b4 > 5000.0)
    ? "Customer is given 10% discount."
    : " customer is given 10% discount."
  ) << endl;
  return 0;
}