Subroutine - Overloading

Overloading

In strongly typed languages, it is sometimes desirable to have a number of functions with the same name, but operating on different types of data, or with different parameter profiles. For example, a square root function might be defined to operate on reals, complex values or matrices. The algorithm to be used in each case is different, and the return result may be different. By writing three separate functions with the same name, the programmer has the convenience of not having to remember different names for each type of data. Further if a subtype can be defined for the reals, to separate positive and negative reals, two functions can be written for the reals, one to return a real when the parameter is positive, and another to return a complex value when the parameter is negative.

In object-oriented programming, when a series of functions with the same name can accept different parameter profiles or parameters of different types, each of the functions is said to be overloaded.

Here is an example of subroutine overloading in C++:

#include using namespace std; double area(double h,double w){ return h*w; } double area(double r){ return r*r*3.14; } int main{ double rectangle_area=area(3,4); double circle_area=area(5); cout<In this code there are two functions of same name but they have different parameters.

As another example, a subroutine might construct an object that will accept directions, and trace its path to these points on screen. There are a plethora of parameters that could be passed in to the constructor (colour of the trace, starting x and y co-ordinates, trace speed). If the programmer wanted the constructor to be able to accept only the color parameter, then he could call another constructor that accepts only color, which in turn calls the constructor with all the parameters passing in a set of default values for all the other parameters (X and Y would generally be centered on screen or placed at the origin, and the speed would be set to another value of the coder's choosing).