Sometimes you want to directly have a reference to the current object, in order to pass it along to other methods or to store it for later use.
In addition, method calls always take place against an object. When you call a method within another method in the current object, is is equivalent to writing this->methodName()
You can also use this to access a member rather than a variable or argument name that "hides" it, but it is (IMHO) bad practice to hide a name. For instance:
void C::setX(int x)
{
this->x = x;
}
