My question is a very simple one.
Normally, when declaring some variable, you put its type before it, like:
int a;
a function pointer may have type like: int(*)(int,int)
, in case we point to a function that takes two integers and returns an integer. But, when declaring such a pointer, its identifier is not after the type, like:
int(*)(int,int) mypointer;
instead, you must write the identifier in the middle:
int(*mypointer)(int,int);
why is this so? Sorry, I know it's an embarrassingly easy question...
Thanks to everybody for replying. A.S.
Function Pointer Syntaxvoid (*foo)( int ); In this example, foo is a pointer to a function taking one argument, an integer, and that returns void. It's as if you're declaring a function called "*foo", which takes an int and returns void; now, if *foo is a function, then foo must be a pointer to a function.
CServer Side ProgrammingProgramming. Function Pointers point to code like normal pointers. In Functions Pointers, function's name can be used to get function's address. A function can also be passed as an arguments and can be returned from a function.
In C, like normal data pointers (int *, char *, etc), we can have pointers to functions. Following is a simple example that shows declaration and function call using function pointer.
I explain this in my answer to Why was the C syntax for arrays, pointers, and functions designed this way?, and it basically comes down to:
the language authors preferred to make the syntax variable-centric rather than type-centric. That is, they wanted a programmer to look at the declaration and think "if I write the expression
*func(arg)
, that'll result in anint
; if I write*arg[N]
I'll have a float" rather than "func
must be a pointer to a function taking this and returning that".The C entry on Wikipedia claims that:
Ritchie's idea was to declare identifiers in contexts resembling their use: "declaration reflects use".
...citing p122 of K&R2.
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