Update ex7_23_24_25.cpp

ex7.24

1."a constructor that takes values for height and width and initializes the contents to hold the given number of blanks;"

In my opinion ,"takes values for height and width' mean  the number of parameters is  two.

2."a constructor that takes values for height, width, and a character to use as the contents of the screen."

I think the characters is fill the screen