As the question says. Is there some difference between the content of them?
Why do we have to declare the variable type before the pointer ????
Does the c process them differently?
Exemple:
typedef struct{
int a;
char b;
} some_st;
int main(){
some_st *p;
int *q;
}
Just a note: I came up with this question after work with linked lists.
Thank you for reading and answering.
the pointers are the same size, but one points to an int and the other one to a struct. The reason to declare them accordingly is that the compiler can tell you when you use them incorrectly.
if you think you're above that, you can use void* for all your pointers, or use a language with even less type checking.
C doesn't define how pointers are represented.
Pointers of different types may have different sizes, different alignments requirements and different bit representaion.
For example this is a completely valid result of an implementation:
sizeof( int* ) != sizeof( long* )
as is :
sizeof( int* ) != sizeof( some_st* )
There is no difference in the size or "structure" of the pointer itself, however the declaration does affect two things:
It tells the compiler how to handle the value being pointed to (int or struct or whatever) - that is, what to assume the pointed type is.
The way pointer arithmetic is being performed. That is what memory location ptr++ or ptr[4] evaluates to. For example, Assuming the struct has, say 12 bytes size, ptr++ will result in the address being incremented by at least 12.
