声明类型的指针?
我刚刚读到我们需要在 C(或 C++)中声明指针时给出指针的类型,即:
I just read that we need to give the type of pointers while declaring them in C (or C++) i.e.:
int *point ;
据我所知,指针存储变量的地址,无论类型如何,地址都占用相同数量的内存.那么,为什么我们需要声明它的类型?
As far as I know, pointers store the address of variables, and address occupies same amount of memory whatever may be the type. So, why do we need to declare its type?
推荐答案
类型安全.如果你不知道 p
应该指向什么,那么就没有什么可以防止像
Type-safety. If you don't know what p
is supposed to point to, then there'd be nothing to prevent category errors like
*p = "Nonsense";
int i = *p;
静态类型检查是防止此类错误的非常强大的工具.
Static type checking is a very powerful tool for preventing all kinds of errors like that.
C 和 C++ 还支持指针运算,它仅在目标类型的大小已知时才有效.
C and C++ also support pointer arithmetic, which only works if the size of the target type is known.
地址占用相同数量的内存,无论我是什么类型
address occupies same amount of memory whatever my be the type
对于当今流行的平台来说确实如此.但有些平台并非如此.例如,指向多字节字的指针可能比指向单字节的指针小,因为它不需要表示字在字内的偏移量.
That's true for today's popular platforms. But there have been platforms for which that wasn't the case. For example, a pointer to a multi-byte word could be smaller than a pointer to a single byte, since it doesn't need to represent the byte's offset within the word.
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