The document discusses overloading binary operators using friend functions and examples of operator overloading. It provides rules for overloading operators and discusses type conversions between basic and class types. Some key points: - Friend functions can be used to overload binary operators like +, replacing member functions. The friend function takes two arguments explicitly. - Strings can be manipulated as class objects with overloaded operators like + instead of using character arrays. - Common operators like [] and -> can be overloaded. - Only existing operators can be overloaded, not new operators created. - Conversion from basic to class types uses constructors. Conversion from class to basic uses conversion functions like operator int().

1. By………..
P.JEEVITHA(181604),
N.THARANI(181621),
II-B.SC MATHS(CA),
To
K.PADMAPRIYA M.SC;M.PHIL;
ASSISTENT PROFFESSOR,
DEPARTMENT OF MATHS(CA),
S.B.K.COLLEGE,
ARUPPUKOTTAI.
By………..
P.JEEVITHA(181604),
N.THARANI(181621),
II-B.SC MATHS(CA),
To
K.PADMAPRIYA M.SC;M.PHIL;
ASSISTENT PROFFESSOR,
DEPARTMENT OF MATHS(CA),
S.B.K.COLLEGE,
ARUPPUKOTTAI.

2. OVERLOADING BINARY OPERATORS USING FRIENDS:
Friend functions may be used in
the place of member functions for overloading a
binary operator,the only difference being that a friend
function requires two arguments to be explicitily
passed to it,while a member function requires only
one.
The complex number program discussed in the
previous section can be modified using a friend
operator function as follows:
❖ Replace the member function declaration by the
friend function declaration.
friend complex operator+(complex, complex);
❖ Redefine the operator function as follows:

3. Complex operator+(complex a, complex b)
{
return complex((a.x+b.x),(a.y+b.y));
}
MANIPULATION OF STRINGS USING OPERATORS:
ANSI C implements strings
using character arrays, pointers and string functions.
There are no operators for manipulating the strings.
For Example,
string3 =string1+string2;
if(string1 >= string2) string = string1;
Strings can be defined as class objects which
can be then manipulated like the built-in types.

4. Class string
{
char*p;
int len;
public:
………
………
};
SOME OTHER OPERATOR OVER LOADING EXAMPLES:
✓ Overloading the Subscript Operator[]
✓Overloading the Pointer-to-member(->) Operator

5. Overloading the Subscript Operator[]
The subscript operator is
normally used to access and modify a specific element
in an array.
Overloading the Pointer-to-member(->)Operator
The pointer-to-member operator
(->) is normally used in conjunction with an object
pointer to access any of the objects members.
RULES FOR OVERLOADING OPERATORS:
❖ Only existing operators can be overloaded . New operators
cannot be created.
❖ Overloaded operators follow the syntax rules of the
original operators.

6. ❖ There are some operators that cannot be overloaded .
❖ We cannot use friend functions to overload certain
operators.
❖ Binary arithmetic operators such as +,-,*,and / must
explicitily return a value.
TYPE CONVERSIONS:
The type of data to the right of an assignment
operator is automatically converted to the type of the variable
on the left.
For Example,
int m;
float x=3.14159;
m=x;
Convert x to an integer before its value is assigned to
m.Thus, the fractional part is truncated.

7. The type conversions are automatic as long as the data types
involved are built-in types.
Three types of situations might arise in the data conversion
between uncompatible types:
❖ coversion from basic type to class type.
❖Conversion from class type to basic type.
❖Conversion from one class type to another class type.
BASIC TO CLASS TYPE:
The conversion from basic type to class is easy to
accomplish. It may be recalled that the use of constructors was
illustrated in a number of examples to inizialize objects.
string :: string (char*a)
{
length=strlen(a);
p=new char [length+1];
strcpy(p,a);
}

8. This construtor builds a string type object from a char* type
a.The variables length and p are data members of the class
string.
For Example,
string s1,s2;
char*name1=“IBM PC”;
char*name2= “Apple Computers”;
s1=string(name1);
s2=name2;
CLASS TO BASIC TYPE :
The constructors did a fine job in type conversion from
a basic to class type.
operator typename()
{
…………
…………(function statement)

9. }
This function converts a class type data to typename.
For Example,
The operator double() converts a class
object to type double,the operator int() converts a
class type object to type int,and so on.
vector :: operator double()
{
double sum=0;
for(int i=0;i<size;i++)
sum=sum+v[i]*v[i];
return sqrt(sum);
}
This function converts a vector to the
corresponding scalar magnitude.