C++ programming language part- 72 Operator overloading
Operator overloading
This session deals with
overloading of operators to make Abstract Data Types (ADTs) more natural and
closer to fundamental data types. To make a user defined data type as natural
as a fundamental data type, the user-defined data type must be associated with
the appropriate set of operators. The fundamental data types with the operator
+, -, /, and *, make the ADTs.
In the following statement
object3=object1+object2; two object of the class named fps_distance
are added and result is stored in the third object. The + operator used to add
integers behaves differently when applied to the ADT fps_distance. Operator
overloading refers to giving additional meaning to the normal C++ operators
when they are applied to ADTs. An operator can be overloaded by defining a
function for it.The function for the operator is declared using the operator keyword. for example, if the ==operator is to
be overloaded in the fps_distance class, the declaration
for the operator function is shown as :
int fps_distance::operator==(fps_distance);
The function definition for the
++operator is
int operator==(fps_distance &Fps2)
{
float fTemp1=iFeet*12+fInch;
float
fTemp2=Fps2.iFeet+Fps2.fInch;
return ((fTemp1==fTemp2)? 1:0);
}
Program 49_1
//operatot
overloading.demo
//file output
class
fps_distance
{private:
int
feet;
float
inch;
public:
fps_distance(int
ft,float in)
{
feet=ft;
inch=in;
}
void operator++(void)
{ feet++;
}
void disp_dist(void)
{
cout<<"The Distance=
"<
};
void main()
{
fps_distance Fps(10,10);
++Fps;
Fps.disp_dist(); } //display
11
The following program overloads the binary operator.
Program 49_2
//operatot
overloading.demo
//file
output
class
fps_distance
{ private:
char str[20];
public:
fps_distance(char
st[20]);
fps_distance();
void
operator+=(fps_distance &);
fps_distance
operator+(fps_distance &);
void
display(void);
};
fps_distance::fps_distance(char
st[20])
{
strcpy(str,st); }
fps_distance::fps_distance()
{
strcpy(str,"nova");}
void
fps_distance::operator+=(fps_distance &Fps2)
{
(strcat (str,Fps2.str));
}
fps_distance
fps_distance::operator+(fps_distance &Fps2)
{ char st[20];
strcpy(st,str);
strcat(st,Fps2.str);
return(fps_distance(st)); }
void
fps_distance::display(void)
{ cout<<"\nstring is "<
void
main()
{ fps_distance
W1("NOVA"),W2("nova"),W3("Dhaka");
W1.display();
W1=W2+W3;
W1.display(); }
