117 Homework Assignment #7

Write a perl program to do the following:

   - Create a hash with these initial keys and values:

        blue         5.62
        red          6.50
        green        4.27

   - Do the following in a loop:

        Ask the user to enter a color.
        If the color is already in the hash,
           display the cost of that color paint.
        else
           If the user input contains any non-lower case letters,
              display an error msg,
           else
              Ask the user for the cost of that color paint.
              If the user input contains any chars other than
                 digits or an optional single period,
                    display an error msg
              else
                 add the new color and cost to the hash.
        If the user enters the word: done  
           when asked for a color,
           end the loop.

   - Then Write all the colors and their values to a text file
      named: file7.txt
      in the current directory.
      Put the color on one line
      and the cost on the next line.
||    Then the next color on the next line
||    then its cost on the next line
||    and so on.

   - Your program must include
      use strict;
      use warnings;