What are the bad habits of C programmers starting to write C++? [closed]

Answer 1

Using C-style casts.

C++ allows you to independently choose whether to allow casts between unrelated types, and whether to allow changes to const and volatile qualifiers, giving considerable improvements to compile-time type safety compared with C. It also offers completely safe casts at the cost of a runtime check.

C-style casts, unchecked conversions between just about any types, allow whole classes of error that could be easily identified by more restrictive casts. Their syntax also makes them very difficult to search for, if you want to audit buggy code for dubious conversions.

Answer 2

Using raw pointers and resources instead of RAII objects.

Answer 3

Not using templates when creating algorithms and data structures (example). It makes things either too localized or too generic

I.e. writing

void qsort(MyStruct *begin, size_t length);  //too localized
void qsort(void *begin, size_t length, 
           size_t rec_size, int(compare*)(void*,void*));  //too generic

instead of

template <class RA_Iter>
void qsort(RA_Iter begin, size_t length);
  //uses RA_Iter::value_type::operator< for comparison

Answer 4

1. Solving the problem instead of creating a class-based monstrosity guaranteed to keep you in health insurance and 401K benefits.

2. Implementing lisp in a single file and doing the design in that.

3. Writing normal readable functions instead of overriding operators?

4. Writing in a style which can be understood by the junior programmers which see good practice as "not writing in C++".

5. Talking to the OS in it's own language.

Answer 5

Not leaving well enough alone, and using C instead.

Answer 6

He thinks that C++ is just a little more different language from C. He will continue programming C masked by C++. No advanced use of classes, the structs are considered less powerful than classes, namespace, new headers, templates, nothing of these new elements are used. He will continue declaring integer vars without int, he will not provide functions prototypes. He will use malloc and free, unsafe pointers and preprocessor to define inline functions. This is just a small list ;)