1.Assume that x is a char variable has been declared and already given a value. Write an expression whose value is true if and only if x is a upper-case letter.

2.Assume that x is a char variable has been declared and already given a value. Write an expression whose value is true if and only if x is a decimal digit (0-9).

3.Assume that x is a char variable has been declared and already given a value. Write an expression whose value is true if and only if x is NOT a letter.

4.

Assume that given, middle and family are three variables of type String that have been assigned values. Write an expression whose value is a String consisting of the first character of given followed by a period followed by the first character of middle followed by a period followed by the first character of family followed by a period: in other words, the initials of the name. So if the values of these three variables were "John" "Fitzgerald" "Kennedy", then the expression's valuewould be "J.F.K.".

5

All windows on the desktop have width and height (as well as numerous other attributes). However the actual contents of the window change both in structure and appearance depending upon what sort of window is displayed (e.g. a word processing window will display text, a color chooser window display a pallette of colors, a file chooser window displays a directory tree, etc). Thus, the details of the method to actual fill the contents of the window must be deferred to the subclasses of the Window class Write the definition of an abstract class, Window, containing the following: two integer instance variables, width and height, two accessor methods, getWidth and getHeight, a constructor that accepts two integers and uses them to initialize the two instance variables (the parameters should be width followed by height), and an abstract void-returning method named paint that accepts no parameters.