Uses of C comma operator [duplicate]

Answer 1

Two killer comma operator features in C++:

a) Read from stream until specific string is encountered (helps to keep the code DRY):

 while (cin >> str, str != "STOP") {
   //process str
 }

b) Write complex code in constructor initializers:

class X : public A {
  X() : A( (global_function(), global_result) ) {};
};