Homework 4
Due Tuesday, October 8, 2002
Solutions, updated with corrections to g, 1e, 2d, and 

a)  response_received | non_interactive | (response_received || non_interactive)
    ----------------------------------------------------------------------------
            T         |        T        |                  T                    
            T         |        F        |                  T                   
            F         |        T        |                  T                    
            F         |        F        |                  F                    

b)  already_made_mistake | patience | !(already_made_mistake && !patience)
    ----------------------------------------------------------------------
              T          |     T    |                 T                   
              T          |     F    |                 F                   
              F          |     T    |                 T                   
              F          |     F    |                 T                   

c)  already_made_mistake | patience | (!already_made_mistake || patience)
    ---------------------------------------------------------------------
              T          |     T    |                 T                  
              T          |     F    |                 F                   
              F          |     T    |                 T                   
              F          |     F    |                 T                   

d)  switch (value % 2)  {
        case 0:
	    cout << "Even integer" << endl;
            break;
        case 1:
            cout << "Odd integer" << endl;
            break;
        default:
            break;
    }

e)  There is a semicolon at the end of the while loop declaration.  This will
     cause the while loop to be "empty" (nothing happens within the loop).
     Also, there is a missing open brace (alternately, an extra close brace).

f)  The angle brackets are facing the wrong direction for an input statement.
    The line should read:
        cin >> value;

g)  This is one set of code that works:
 	int ctr = 1;
	while (ctr <= 20)
	{
	    cout << ctr << " ";
	    if (ctr % 5 == 0)
                cout << endl;
            ctr++;
	}

Chapter 4 problems:
1a) False - Since logical expressions generate a 1 for true and 0 for false,
    the result can be stored in an int variable.
1b) False - A semicolon after an if statement will cause the action of the
    if statement to be empty, meaning the statements after the if will always
    be executed.
1c) False - Every if does not necessarily need a corresponding else, but
    every else needs a corresponding if.
1d) True - The programmer probably meant to say if (score==30), but given the
    error that they typed (score=30), the expression score=30 takes the value
    30.  This is nonzero, so the expression evaluates to true.  The statement
    is ALWAYS executed.
1e) False - it should say evaluates to false if either ch < 'A' or
    ch > 'Z' 
1f) False - a pair of braces is missing.  The else therefore has no matching
    if.  Therefore, the code does not compile.
1g) False - it should evaluate to an integer type
1h) False - The statement is also true if x equals 0.
1i) False - != is a relational operator, not a logical operator 
1j) True

2d) (i), if you think the missing quote was a typo and you generously inserted
    it, or (iii) if you realized that the missing " causes the program to not
    compile
2e) (iii)

8) beta = 7  (3 + 3 = 6, then add 1 to get 7.  Note that the programmer
   probably meant to put in break statements at the end of each case, but
   forgot.  The programmer also forgot a default case)

Chapter 5 problems:
1a) False - Counter-controlled while loops require that you initialize the
    control variable before you enter the loop.
1b) True - the body will not be executed if the expression is intially false
1c) False - In an infinite while loop, the control expression always
    evaluates to true (that's why the program never quits).
1d) True
1e) True
1f) True
1g) True
1h) False - When a while loop terminates, the control goes to the statement
    immediately following the while loop.

3) 5

4) 1 3 5 7 9

7) Sum = 158