Expected initializer before ‘Foo’

From Cppsyntax

You can get the error

 expected initializer before ‘Foo’

if you use Java syntax instead of C++ syntax for making a subclass.

WRONG

 #include "Foo.h"
 class Bar extends Foo
 {
   // stuff  
 };

RIGHT

 #include "Foo.h"
 class Bar: public Foo
 {
   // stuff  
 };

It also happens when you forget to put a semicolon at the end of a class definition:

WRONG

 #include "Foo.h"
 class Bar
 {
   public:
     int aMethod();
 }  // without semicolon
 int Bar::aMethod() { return 0; }  // compiler signalizes error at this line

RIGHT

 #include "Foo.h"
 class Bar
 {
   public:
     int aMethod();
 };
 int Bar::aMethod() { return 0; }