The arguments distinguish functions with the same name 
(functional polymorphism). The name alone does not 
necessarily identify a unique function.  However, the name 
and its arguments (signatures) will uniquely identify a 
function.
In real life we see suppose, in class there are two guys 
with same name, but they can be     easily identified by 
their signatures. The same concept is applied here.
ex:
class person
{
public:
char getsex();
void setsex(char);
void setsex(int);
};
In the above example we see that there is a function setsex
() with same name but with different signature.