Programming and Problem Solving with Java

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4.How would you change the code you wrote for Question 3 so that it writes an

error message if the value is not 1 , 2 , or 3? (pp. 438–442)

5.What is the primary difference between a whileloop and a doloop? (pp.

442–445)

6.A certain problem requires a count-controlled loop that starts at 10 and counts

down to 1. Write the heading (the first line) of a forstatement that controls this

loop. (pp. 445–447)

7.What Java looping statement would you choose for a loop that is both count-

controlled and event-controlled and whose body might not execute even

once? (p. 448)

8.What is the difference between an expression and an expression statement in

Java? (pp. 448–450)

Answers

1. try
   {
   intValue = Integer.parseInt("123");
   }
   catch(NumberFormatException except)
   {
   System.out.println(except.getMessage);
   }


2. Throwable


3. switch(nameVal)
   {
   case 1 : outData.println("Mary");
   break;
   case 2 : outData.println("Lynn");
   break;
   case 3 : outData.println("Smith");
   break; // Not required
   }


4. switch(nameVal)
   {
   case 1 : outData.println("Mary");
   break;
   case 2 : outData.println("Lynn");
   break;
   case 3 : outData.println("Smith");
   break;
   default: outData.println("Invalid name value.");
   break; // Not required
   }


5. The body of a doloop always executes at least once; the body of a whileloop may not execute at all.6.for
   (count = 10 ; count >= 1 ; count--)7.A while(or perhaps a for) statement 8. An expression becomes
   an expression statement when it is terminated by a semicolon.