Program: Bounce
By:  Ben Axelrod

     This is a bouncing text program.  To use, just enter the parameters when 
prompted, watch the show, then press enter when the text is done bouncing.  The 
range of allowed values are displayed on the screen.  If you enter a value that is 
not allowed, it takes you back to the start of the program to re-enter the values.  
I have found that the program works best with smaller strings, (like one letter), 
but any string will work.  I think the coolest feature of this program is the 
variable tail of your text.  This allows you to see the last few (or many) places 
where the text was, and therefore see the parabolic motion of the text better.  You 
can also enter 1 for the tail to get no tail at all.  This tail is achieved by 
creating a second string with the same length as the text, but all spaces.  It 
follows the text and erases the previous texts.  The initialization is the second 
string being built up.  The longer the string, the longer the initialization time.  

Features of the program include:
  * Can choose start coordinates, X and Y.
  * Can choose horizontal speed of text, 0 for straight drop.
  * Can choose coefficient of restitution.
  * Can choose length of tail, or no tail at all.
  * Parameter “M” can be changed (by editing the program) to raise the “floor” that 
    the text bounces off of.  Default is 56.
  * After the bouncing has stopped, and the text is moving horizontally only, it 
    slows to a stop, (can be seen better with larger speeds).
  * Length of your string is calculated, so it never goes off the screen to the 
    right.
  * Text bounces off both sidewalls.
  * Checks for forbidden parameters.

-----Known Bugs-----
     This program is by no means perfect and it has a few bugs.  If something goes 
wrong, it is probably just a result of the chosen variables.  Start the program 
again, and alter the values you set at the beginning.  The problem should go away.  
     Since I used the length( function to calculate the length of the string, if you 
enter something like SIN( you will get an unwanted permanent tail.  That is because 
it has many characters, but the calculator only counts it as one.  If you feel the 
need to put a function like SIN( in your string, type it out with normal characters 
to avoid this.  


Questions, comments?  Email me: bmaxelro@syr.edu