If necessary, create a new project named intermediate23 project and save it in the
cpp8\chap13 folder. also create a new source file named intermediate23.cpp. write
a program that displays the color of the item whose item number is entered by the
user. all item numbers contain exactly seven characters. all items are available in four
colors: blue, green, red, and white. the fourth character in the item number indicates
the item’s color, as follows: a b or b indicates blue, a g or g indicates green, an r or r
indicates red, and a w or w indicates white. if the item number does not contain
exactly seven characters, or if the fourth character is not one of the valid color
characters, the program should display an appropriate message. use a sentinel value to
end the program. save and then run the program. test the program using the following
item numbers: 123b567, 34ag123, 111r222, 111w222, 123, 1234567, and 111k456.

use the len() and substring methods (and of course there are others) to perform the necessary work.