Differentiating Prefix and Postfix Operators
There is one problem with defining both the prefix and postfix operators: Normal overloading cannot distinguish between these operators. The prefix and postfix versions use the same symbol, meaning that the overloaded versions of these operators have the same name. They also have the same number and type of operands.
To solve this problem, the postfix versions take an extra (unused) parameter of type int. When we use a postfix operator, the compiler supplies 0 as the argument for this parameter. Although the postfix function can use this extra parameter, it usually should not. That parameter is not needed for the work normally performed by a postfix operator. Its sole purpose is to distinguish a postfix ...
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