'a' - ('a' - 'A') == 'A'
, or, 'a' - 32 == 'A'
.
Subtracting 32 from a lower case character results in the corresponding
upper case character (in ASCII).
Here is the complete design of the program. Glance over it to get the general idea. Its individual routines are explained in the following pages. This design uses more subroutines than usual because its purpose is to show subroutine linkage.
A subroutine starts with a pill-shaped box
that shows the name of the subroutine.
A box with double vertical lines for its sides
(like doLines
in main
)
designates a subroutine call.
The program starts execution with main
.