Teach Yourself Borland C++ in 14 Days - portal

102 Day 4
NOTE
Rect::Rect(int _left, int _top, int _right , int _bottom) :
left(_left),
top(_top),
bottom(_bottom),
right(_right)
{
}
Notice two things in this code snippet. First, notice that the initializer list is preceded by a
colon. (The colon is at the end of the function header, so you may not have noticed it.) Notice
also that each variable in the initializer list is followed by a comma except the last variable.
Forgetting either of these two things will cause compiler errors.
On Day 3 I talked about references. You can have a class data member
that is a reference, but the reference can only be initialized in the
initializer list of the class and nowhere else. Here’s an example:
class MyClass {
public:
MyClass();
// other public stuff
private:
OtherClass& other;
// other private stuff
};
MyClass::MyClass() :
other(*new OtherClass) // must do this here!
{
}
Attempts to initialize the reference anywhere else will result in compiler
errors.
In most cases it doesn’t matter whether you initialize your data members in the body of the
constructor or the initializer list. I have done it both ways, but I prefer the initializer list.
Destructors
The destructor is a special function that is automatically called just before the object
is destroyed.
The destructor could be considered the opposite of the constructor. It is usually used to free any
memory allocated by the class or do any other cleanup chores. A class is not required to have
a destructor, but if it does, it can have only one. A destructor has no return value and takes no
parameters. The destructor’s name must be the name of the class preceded by a tilde (~).
NEW TERM