malloc returns void*, which is a generic pointer that can point to any type of data. The (char*) is an explicit type conversion, converting the pointer returned by malloc from a pointer to anything, to a pointer to char. This is unnecessary in C, since it is done implicitly, and it is actually recommended not to do this, since it can hide some errors.
If you need the code to compile as C++ too, and not just as C, you will however need the explicit conversion, since C++ doesn't perform the implicit conversion.
