Pointer Confusion: Solve the Mystery

[martix]

There something really fishy going on here and I can't put my finger on it...
Here is the situation in condensed form:

	WordSt **stpt, *starr; //stpt - pointer to start of array; starr - array of pointers to the structs
...
		stpt=malloc(count*sizeof(starr*)); //syntax error : ')' - what's with that anyway?
		...
			starr[wz]=malloc(sizeof(WordSt)+len*sizeof(char)); //C2679: binary '=' : no operator found which takes a right-hand operand of type 'void *' (or there is no acceptable conversion) Trying to convert it doesn't cut it either...
			starr[wz]->len=len; //Says it need '.' When I put '.'(as in (*starr[wz]).len) it says "illegal indirection". Also any version with -> doesn't work

What I know - indexing is also a form of memory manipulation, so it should work. And (*b).el == b->el. Btw first option gives me an automatic menu for choosing between the elements, no such luck with the second one.
Help!

 

[chroot]

There are so many things wrong here, it's hard to even know where to begin.

1) Give your variables meaningful names.
2) stpt is not a pointer, it's a pointer to a pointer. malloc returns a pointer, so you don't want to be assigning the result of malloc to stpt.
3) The syntax "starr*" is meaningless in the context you used it.
4) You're assigning values to starr[wz], but starr is a garbage pointer, and this will cause a segfault.
5) You need to cast the void* that malloc returns into the WordSt* you want it to be.
6) starr[wz] is a structure, not a pointer to a structure, so you should not be using ->, you should just be using dot-notation. You don't need to dereference starr[wz] at all, as starr[wz] is not a pointer. That's what "illegal indirection" means.

- Warren

 

[quicknote]

It seems like there may be some confusion with how pointers are being used in this code. The use of starr and stpt as pointers to an array and start of an array respectively can be confusing. Additionally, the syntax error with the malloc function and the error with accessing the elements of the starr array suggest that there may be issues with how the pointers are being dereferenced.

To solve this mystery, it may be helpful to review the basics of pointers and their syntax in C. Additionally, it may be useful to use a debugger or print statements to track the values of the pointers and see where the errors are occurring. It may also be helpful to carefully review the purpose and intended use of each pointer in the code.

In general, pointer confusion can be a common issue in programming, but with careful attention to detail and a solid understanding of pointer syntax, it can be solved.