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You’ve
already learned about a number of variable types,
including unsigned integers and characters. The
type of a variable tells you quite a bit about it.
For example, if you declare Height and Width to
be unsigned integers, you know that each one can
hold a number between 0 and 65,535, assuming an
integer is two bytes. That is the meaning of saying
they are unsigned integers; trying to hold anything
else in these variables causes an error. You can’t
store your name in an unsigned short integer, and
you shouldn’t try.
Just
by declaring these variables to be unsigned short
integers, you know that it is possible to add Height
to Width and to assign that number to another number.
The
type of these variables tells you:
·
Their size in memory.
·
What information they can hold.
·
What actions can be performed on them.
More
generally, a type is a category. Familiar types
include car, house, person, fruit, and shape. In
C++, the programmer can create any type needed,
and each of these new types can have all the functionality
and power of the built-in types.
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