Question

I’m doing a huffman encoding algorithm in C and got in a problem here.

I have two different .h files that will use this struct:

typedef struct no{
  int qtd;
  char c;
  struct no* esq;
  struct no* dir;
}no;

So, my arv_huffman.h has that typedef and typedef no** arvHuffman

My other .h, heap.h, includes “arv_huffman.h” and uses typedef no* heap

Both files have no other implementations. The message I get when I try to compile is:

arv_huffman.h:11: error: redefinition of ‘struct no’
arv_huffman.h:16: error: conflicting types for ‘no’
arv_huffman.h:16: note: previous declaration of ‘no’ was here
arv_huffman.h:18: error: conflicting types for ‘arvoreHuff’
arv_huffman.h:18: note: previous declaration of ‘arvoreHuff’ was here

lines have the following code

arv_huffman.h:11: "typedef struct no{"
arv_huffman.h:16: "}no;"
arv_huffman.h:18: "typedef no** arvoreHuff;"

What’s going wrong and how do I fix it.

Answer 1

You forgot to put header guards in your .h

Since the guards aren’t present, it is seeing the same definition twice, and thinks you are redefining the struct.