Top down program design is an approach to program design that starts with the general concept and repeatedly breaks it down into its component parts. In other words, it starts with the abstract and continually subdivides it until it reaches the specific. Consider creating the prime factorization of a number like 1540. The steps involved might look like:
1540
2 x 770
2 x 2 x 385
2 x 2 x 5 x 77
2 x 2 x 5 x 7 x 11
Top down program design works the same way. We start with the overall objective and wind up with a series of steps needed to accomplish it.
In your question whereas there is a class named window and it would be like this:
class window {
//code here
}
Next is there is a function called close and freeresource and it goes like this:
class window{
function close( ){
//code here
}
function freeresource( ){
// code here
}
public destruct (){
this.close();
this.freeresource();
}
}
The last code function destruct invokes the function close and freeresource. Hope this would help
