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.

   

Use a Word document to paste your screenshots of your code and the results of execution. Number the questions and annotate your answers, when appropriate, to show your understanding. 

#.  Which of these are Boolean expressions?  Assume the variables are of 
    type ``int``::

        true
        "false"
        x = 3
        n < 10
        count == 22
        x <= 2 || x > 10
        x == 2 || 3
        1 < y < 10
        
#.  What are the values of these expressions?  Be able to explain::

        2 < 3 && 4 < 5
        2 < 3 && 4 < 3
        2 < 3 || 4 < 5
        2 < 3 || 4 < 3
        3 < 2 || 4 < 3
        2 < 3 || 4 < 5 && 4 < 3
        
#.  Assume  ``IsBig(x)`` returns a Boolean value.
    Remove the redundant part of this statement::
    
        if (IsBig(x) == true)
           x = 3;

#.  Add parentheses in ``2 < 3 || 4 < 5 && 4 < 3`` to get a different result. 
    

#.  What is printed when the following code executes and x has been set to 0 and y to 3?::

      if (x > 0 && (y / x) == 3)
      {
         Console.WriteLine("first case");
      }
      else
      {
         Console.WriteLine("second case");
      }

#.  What does the following code print when x has been set to 2000?::

      if (x < 0)
      {
         Console.WriteLine("x is negative");
      }
      else if (x == 0)
      {
         Console.WriteLine("x is zero");
      }
      else
      {
         Console.WriteLine("x is positive");
      }
                     
           
#.  Assume ``x`` and ``y`` are local ``int`` variables.  
    Code fragments are separated by a blank line below.  
    Pairs of the fragments are logically equivalent, but not necessarily with
    a directly adjacent fragment. Match the pairs. Be sure you understand
    when different pairs would behave differently.  Caution: 
    there is some pretty awful code here, that we would *hope* you would never
    write, but you might need to correct/read! 
    In each equivalent pair, which code fragment is more professional?  ::
    
       if (x > 7) {    //a
          x = 5;
       }
       y = 1;

       if (x > 7) {    //b
          x = 5;
          y = 1;
       }
    
       if (x > 7)      //c
          x = 5;
          y = 1;       
    
       if (x > 7) {    //d
          x = 5;
       }
       else {
          y = 1;
       }
       
       if (x > 7)      //e
          x = 5;
       else if (x <= 7) {
          y = 1;
       }
 
       if (x > 7) {    //f
          y = 1;
       }
       if (x > 7) {
          x = 5;
       }
   
#.  Same situation as the last problem, and same caution,
    except this time assume the fragments 
    appear in a function that returns an ``int``. 
    In each pair of equivalent fragments, which is your preference?  ::
    
        y = 1;         //a
        if (x > 7) {
           return x;
        }
        
        if (x > 7) {   //b
           return x;
        }
        y = 1;
        
        if (x > 7) {   //c
           return x;
        }
        else {
           y = 1;
        }
        
        if (x > 7) {   //d
           return x;
           y = 1;
        }
        
        if (x > 7) {   //e
           y = 1;
           return x;
        }
        y = 1;
        
        if (x > 7) {   //f
           return x;
        }
        
        if (x > 7);    //g
           return x;
        
        return x;      //h

#.  Same situation as the last problem, and same caution::

        if (x > 5)        //a
           if (x > 7)
               return x;
        else
           y = 1;
           
        if (x > 5)  {     //b 
           if (x > 7)
               return x;
        }
        else {
           y = 1;
        }
           
        if (x > 7)        //c
           return x;
        if (x <= 5)
           y = 1;
           
        if (x > 7)        //d
           return x;
        if (x > 5)
           y = 1;

#. The following code should print x is greater than 0. However, the code has 
   errors. Fix the code so that it compiles and runs correctly. Run the program 
   several times with different values of x to test both if and else branches.::

      public class Test1
      {
         public static void Main(String[] args)
         {
            int x = 3;
            if (x > 0
                  Console.WriteLine("x is greater than 0")
            else
                  Console.WriteLine(x is less than or equal 0");
         }
      }

   - Copy the code to your Word file and mark your changes in red bold font. 
   - You use either csharprepl or VS Code to test the code. 



.. #.  When reading a verbal description of a problem to solve, 
..     what are some words or phrases that suggest that some version of 
..     an ``if`` statement will be useful?

        
.. #.  Correct the last two entries in the first problem, supposing the user
..     meant "x could be either 2 or 3" and then
..     "y is strictly between 1 and 10".
    
.. #.  Suppose you have four possible distinct situations in your algorithm, 
..     each requiring a totally
..     different response in your code, 
..     and at most one of the situations will occur, so 
..     possibly nothing will happen that needs a response at all.
..     Have many times must you have ``if`` followed by
..     a condition?        


.. Suppose you have four possible distinct situations in your algorithm, 
..     each requiring a totally
..     different response in your code, 
..     and exactly one of the situations is sure to occur.
..     Have many times must you have ``if`` followed by
..     a condition?

.. #.  Write an equivalent (and much shorter!) statement with no ``if``:: 

..         if (x > 7)  
..            return true;
..         else
..            return false; 
           
.. #.  Write an equivalent (and much shorter!) statement with no ``if``:: 

..         if (x > 7)  
..            isSmall = false;
..         else
..            isSmall = true;