C++98: NTCTS

In the C++ standard, NTCTS stands for "null-terminated character-type sequence".
Reference: C++ Common Knowledge by Stephen C. Dewhurst. Addison-Wesley, 2005., p. 205.

C++98: Class Templates

Class templates must be specialized explicitly.
Reference: C++ Common Knowledge by Stephen C. Dewhurst. Addison-Wesley, 2005., p. 209.

C++98: Cast Operators

Although, static_cast, dynamic_cast, reinterpret_cast, and const_cast all look like templates; they are not. They are operators.
Reference: C++ Common Knowledge by Stephen C. Dewhurst. Addison-Wesley, 2005., p. 210.

C++98: Overloaded Operators

An overloaded operator has the same precedence as the original operator.
Reference: C++ Strategies and Tactics by Robert B. Murray. Addison-Wesley, 1993., p. 33.

C++98: Class Member Operators

If the following operators are overloaded, they must be class members: =, [], (), ->
Reference: C++ Strategies and Tactics by Robert B. Murray, Addison-Wesley, 1993., p. 46.

C++98: Copy Constructors

A copy constructor of the following form is illegal in C++: A::A(A).The argument should be const A &.
Reference: C++ Strategies and Tactics by Robert B. Murray, Addison-Wesley, 1993., p. 60.

C++98: Nested Classes

Nested classes can derive from each other.
Reference: C++ Strategies and Tactics by Robert B. Murray, Addison-Wesley, 1993., p. 75.

C++98: Deriving a Class from an int

You cannot derive a class from an int.
Reference: "C++ Strategies and Tactics" By Robert B. Murray. Addison-Wesley, 1993., p. 192.

C++98: Dangling Pointer

stringstream ss("MyString");const*p=ss.str().c_str(); makes p a dangling pointer. The invisible temporaries created from str() and c_str() live only until the last ';'.

It might look like it works, but if you add some more code following const*p=..., you may see your string corrupted. I just added stringstream ss2("Another String"); and this corrupted the data to which p points.

This kind of problem is fun (sarcasm, because it is not fun) to debug.

Reference: First-hand experience.

Inline Functions

You cannot declare main() inline.

assign()

The function assign() is a member of the following containers: vector, string, deque, and list.
Reference: Effective STL by Scott Meyers. Addison-Wesley, 2001., p. 37.

STL Container Destructors

None of the Standard STL containers have virtual destructors.
Reference: Effective STL by Scott Meyers. Addison-Wesley, 2001., p. 37.

Memory Leaks

The following statement leaks 10 bytes of memory:
operator new(10);
Reference: Effective STL by Scott Meyers. Addison-Wesley, 2001., p. 51.

STL Algorithms

These STL algorithms require that their input be sorted: binary_search, upper_bound, set_union, set_difference, merge, includes, lower_bound, equal_range, set_interaction, set_symmetric_difference, and inplace_merge.
Reference: Effective STL by Scott Meyers, Addison-Wesley, 2001. p. 147.

unique() and unique_copy()

The STL algorithms, unique() and unique_copy() do not require their input to be sorted. The result might be surprising though, since only duplicates that are adjacent are removed.
Reference: Effective STL by Scott Meyers, Addison-Wesley, 2001., p. 147.