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

One seldom used, but handy C++ idiom is the use of the ?: operator during the constructor chain.

class Sample
{  
    const char * ptr;
    const bool  freeable;

    Sample(const char * optional):
        ptr( optional ? optional : new char [32]),
        freeable( optional ? false : true ) {}
    ~Sample( )  { if (freeable) delete[] ptr; }
}  

C++ doesn't allow const values to be changed inside the body of the constructor, so this avoids const-casts.