（char *）和char *之间有什么区别？

Question

in the line: ((string*)userp)->append((char*)contents, size * nmemb); Why use (char*) or (string*) as opposed to char* or string ? Trying to use char* or string results in an error Also, what does the operator -> do? It seems like it is just taking the place of str.append(var, pos);

Answer 1

(string*) is a cast to pointer to string and string is a class string. (char*) is a cast to pointer to char and char* is a pointer to char. the -> operator accesses the attributes or methods of a pointer to a class