I'm trying to create a struct to be used in a Linked List that looks like this:

```
#ifndef MYGREP_H
#define MYGREP_H

typedef struct occurrenceType Occurrence;

struct occurrenceType {
    char* line;
    int lineNumber;
    int wordNumber;
    Occurrence *next;
};

#endif

```

but when I try to allocate memory using sizeof(Occurrence) I get the error "Invalid application of 'sizeof' to incomplete type 'Occurrence.' I've tried several different structure declaration formats with no luck. Can someone tell me what I'm doing wrong? Thanks!