Comp 110

Homework Assignment #2

Due: 9/30/2009

 

Design algorithms for the following two problems.  Your main algorithm should contain just the main steps, and for each step that is non trivial, develop a separate algorithm for it.  These will become methods in your program.  You may want to develop a top-down design diagram for your algorithm like the one below for the printCalendar problem.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


  1. A palindromic prime is a prime number and also palindromic.  For example, 131 is a prime and also a palindromic prime.  So are 5 and 929.  Develop an algorithm that displays the first 100 palindromic prime numbers.  Display 10 numbers per line and align the numbers properly, as follows:

 

     2    3    5    7   11  101  131  151  181  191

   313  353  373  383  727  757  787  797  919  929

    

     (Compare with problem 3.27 on page 176 of the textbook.)

 

  1. Craps is a popular dice game played in casinos.  Design an algorithm for the following version of the game:

 

Roll two dice.  Each die has six faces representing values 1, 2, . . ., and 6, respectively.  Check the sum of the two dice.  If the sum is 2, 3, or 12 (called craps) you lose; if the sum is 7 or 11 (called natural), you win;  if the sum is another value (i.e., 4, 5, 6, 8, 9, or 10), a point is established.  Continue to roll the dice until either a 7 or the same point value is rolled.  If 7 is rolled, you lose.  Otherwise, you win.

 

            Your algorithm should be for a single player.  Here are some sample runs:

 

                        You rolled 5 + 6 = 11

           You win

 

           You rolled 1 + 2 = 3

           You lose

 

           You rolled 4 + 4 = 8

           Point is 8

           You rolled 6 + 2 = 8

           You win

 

           You rolled 3 + 2 = 5

           Point is 5

           You rolled 2 + 5 = 7

           You lose

 

     (Compare with problem 5.29 on pages 176 & 177 of the textbook.)