C ++ overload auto-increment/subtraction Operators

Used as a class member.

Prefix: First add/subtract 1, then value; suffix: First value, plus/minus 1.

The prefix is the left value and returns a reference. The suffix is the right value and the return value.

An int parameter is added to the suffix for differentiation. The compiler will pass a useless 0 as the real parameter.

Call the prefix version in the suffix implementation.

Explicit call: prefix xxx. operator ++ (); suffix xxx. operator ++ (0)

<Iostream> <stdexcept> CheckedPtr (* B, * CheckedPtr & ++ & -- CheckedPtr ++ (-- (*** & CheckedPtr: ++ (cur = std :: out_of_range (++ * & CheckedPtr: -- (cur = std :: out_of_range (-- * ++ (* ++ * -- (* -- * ia [++ (std: out_of_range & <e. what () <