开发者

Is the C++ * operator "already overloaded?"

My C++ teacher thinks that the * operator in standard C++ is "already overloaded," because it can mean indirection or multiplication depending on the context. He got this from C++ Primer Plus, which states开发者_Python百科:

Actually, many C++ (and C) operators already are overloaded. For example, the * operator, when applied to an address, yields the value stored at that address. But applying * to two numbers yields the product of the values. C++ uses the number and type of operands to decide which action to take. (pg 502, 5th ed)

At least one other textbook says much the same. So far as I can tell, this is not true; unary * is a different operator from binary *, and the mechanism by which the compiler disambiguates them has nothing to do with operator overloading.

Who is right?


Both are right as the question depends on context and the meaning of the word overloading.

"Overloading" can take a common meaning of "same symbol, different meaning" and allow all uses of "*" including indirection and multiplication, and any user-defined behavior.

"Overloading" can be used to apply to C++'s official operator overloading functionality, in which case indirection and multiplication are indeed different.

ADDENDUM: See Steve's comment below, on "operator overoading" versues "token overloading".


I believe you are. The dereference op and the mult. op are different operators, even if written the same. same goes for +,-,++,--, and any other I may have forgotten.

I believe the book, in this paragraph, refers to the word "overloaded" as "used in more than 1 way", but not by the user. So you could also consider the book as being correct... also depends if you're referring to the overloading of the * operator or of the multiplication operator (for example).


It's overloaded in the sense that the same character is used to mean different things in different places (e.g. pointer dereference, multiplication between ints, multiplication with other built-in types, etc.).

Generally, though, "operator overloading" refers to defining an operator (that has the same symbol as a built-in one) using custom code so that it does something interesting with a user defined type.

So... you're both right :-)

0

上一篇:

下一篇:

精彩评论

暂无评论...
验证码 换一张
取 消

最新问答

问答排行榜