Chapter Review 
=========================

- Note that the course policy is that you should not use generative AI 
  without authorization. If you are suspected to have used generative AI 
  and not able to explain/reproduce your work when requested, all your 
  **related assignments throughout the semester will be regraded as 0.**

- Prepare this assignment using a Word document.
- Number and write answers under each question.
- Paste code screenshots when required.
  

#.  When might you prefer a ``for`` loop in place of a ``while`` loop?
    What do you gain?

#. When might you prefer a while loop or a foreach instead of a for loop?

#.  Describe in general when a ``foreach`` loop is going to be easier to use 
    than a ``while`` loop.
    
#.  Each sentence below introduces a problem.  
    What words/combinations suggest a loop/repetition?
    
    #. Square each number from 1 to n.
    #. Respond until the user says to stop.
    #. Repeat the process until the width is < .00001.
    #. Count the vowels in the sentence that you are given.
    #. See if there are any double letters in the word that you are given.
    
#.  Compare do-while and while loops: 
    How do you think about which one to use?

#.  In general, what causes an infinite ``while`` loop?

#.  A ``while`` loop is generally terminated when the program evaluates the
    condition in its heading and it becomes false.  
    How else can a program exit from a ``while`` loop?
    
#.  When inside a loop,
    a return statement should generally only appear as a *sub-statement*
    of what kind of statement?
    
#.  Which of these conditions is safer in general, with *arbitrary* 
    ``string`` ``s`` and 
    ``int`` ``i``?  ::

         s[i] != '#' && i >= 0 && i < s.Length
         
         i >= 0 && i < s.Length && s[i] != '#' 
         
#.  What is printed?  ::

        //          012345678901234567890
        string s = "Is coding cool? Yes!"
        Console.WriteLine(s.Trim()); 
        string t = s.Substring(9, 8);
        Console.WriteLine(t.Replace(" ", "/")); 
        Console.WriteLine(t.Trim().Replace(" ", "/")); 
        Console.WriteLine(s.StartsWith("is"));
        Console.WriteLine(s.ToLower().StartsWith("is"));
        int i = s.IndexOf("co"), j = s.IndexOf("co", i+1),
            k = s.IndexOf("co", j+1);
        Console.WriteLine(i + " " + j + " " + k);