Assume the existence of a class named window with functions named close and freeresources, both of which accept no parameters and return no value . write a destructor for the class that invokes close followed by freeresources.

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 

Solution: the categorization of functional and non-functional requirement are as follows: some of the more typical functional requirements include: • business rules• transaction corrections, adjustments and cancellations• administrative functions• authentication• authorization levels• audit tracking• external interfaces• certification requirements• reporting requirements• historical data• legal or regulatory requirementswhile,some typical non-functional requirements are: • performance – for example response time, throughput, utilization, static volumetric• scalability• capacity• availability• reliability• recoverability• maintainability• serviceability• security• regulatory• manageability• environmental• data integrity• usability• interoperability