This question already has answers here:
Why is the asterisk before the variable name, rather than after the type?
(12 answers)
Closed 7 years ago.
I Just want to know what is the difference between the following way of assigning a pointer. i was watching a C tutorial online and couldn't understand why he used the second pointer like this char * buffer;. Instead of char *buffer
Like the way I use the pointer in all my C learning. is it style?
e.g
FILE *pFile;
struct product *next;
does it matter where you put the asterix (pointer) or what is the meaning behind it?
Nope, there is no difference, it's a matter of preference.
I tend to put it as struct product* next because it makes it clearer that the type of next is product*, AKA a pointer to a product. But different people advocate different things.
Related
This question already has answers here:
How do you implement a class in C? [closed]
(16 answers)
Closed 3 years ago.
After reading this page, I already know how to implement non-copyable
classes in C++.
(How do I make this C++ object non-copyable?)
Now I want implement non-copyable in C,
But I don't find similar code in C.
So I want to ask how to implement in C.
You can do this using opaque pointers. The idea is:
You define a struct somewhere and you define all of its operations in terms of a pointer to that struct. That would probably be a standalone compilation unit.
The consumers of your struct only get a declaration but not the full definition of that struct, which means that they don't know the layout or even the size of the struct. It follows that they are able to receive, store, and pass around any pointers to that struct, but not values of it.
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What is std::decay and when it should be used?
(2 answers)
Closed 6 years ago.
We know that compiler will decay array/function to pointers when needed(according to context), then when is the time we should explicitly use std::decay?
Is there any task that requires us to use it, or else, compiler doesn't know how to handle it?
Thanks.
Simply put, decay::type is the identity type-transformation except if T is an array type or a reference to a function type. In those cases the decay::type yields a pointer or a pointer to a function, respectively.
For more detail please see this https://stackoverflow.com/a/25732651/1691223
This question already has answers here:
When should I pass or return a struct by value?
(9 answers)
Closed 7 years ago.
I know the difference between pass by value and pass by reference. I use them and understand how they work in the codes that I've dealt so far. However, I'm looking for a general rule. What is generally the best time to use pointers and what is the best to use actual values? Examples are much appreciated.
As a general rule, pass-by-value for basic types (int, char, etc.), and pass-by-pointer (or better, pass-by-reference) for big data as struct.
Thinking of a struct with 1000 data members, and the cost to copy that gigantic data to a function. It'd be much quicker to pass-by-pointer or pass-by-reference in that case.
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
What is void* and to what variables/objects it can point to
What does void* represent in C?
Please give a reason for the use, too...
void * is a "typeless" pointer in C, that is, a pointer that may point to an object of any type. It is used if one does not know the type of the data to be stored beforehand.
This question already has answers here:
Closed 12 years ago.
Possible Duplicate:
What is the point of function pointers?
hi all,
I want to get the basic and concrete idea of function pointers in C language.
ie 1) its usage in C
2) main applications it is currently using
3) unique features
4) its scope in embedded applciations etc
Hoping your co operation in this too.
__Kanu
Function Pointers are pointers, that is variables, which point to the address of a function.
Nice example here. Also this answer is a must read.