What are some C++ related idioms, misconceptions, and gotchas that you've learnt from experience?

Question

What are some C++ related idioms, misconceptions, and gotchas that you\'ve learnt from experience?

An example:

class A
{
  public: 
  char s[1024];
  cha         


        

Answer 1

Since we're all ignoring the OP and instead posting our favourite cool tricks...

Use boost (or tr1) shared_ptr to maintain a class invariant at runtime (kind of obvious, but I haven't seen anyone else do it):

#include 
#include 
#include 
#include 
using namespace std;
using namespace boost;

class Foo
{
public:
    Foo() : even(0)
    {
        // Check on start up...
        Invariant();
    }

    void BrokenFunc()
    {
        // ...and on exit from public non-const member functions.
        // Any more is wasteful.
        shared_ptr checker(this, mem_fun(&Foo::Invariant));

        even += 1;
        throw runtime_error("didn't expect this!");
        even += 1;
    }

private:
    void Invariant() { assert(even % 2 == 0); }
    int even;
};