This is actually a function declaration. The function is called myStack and it returns a vector<Site>. What you actually want is: The type of neighbours at the moment will store copies of the objects, not references. If you really want to store references, I recommend using a std::reference_wrapper (rather than using pointers):
Arrays can only be passed by reference, actually: This prevents you from doing things like: To be able to pass an arbitrary size array to foo, make it a template and capture the size of the array at compile time: You should seriously consider using std::vector, or if you have a compiler that supports c++11, std::array.
From Understanding Weak References, by Ethan Nicholas: Weak references A weak reference, simply put, is a reference that isn’t strong enough to force an object to remain in memory. Weak references allow you to leverage the garbage collector’s ability to determine reachability for you, so you don’t have to do it yourself. You create a weak reference … Read more
In this case, double means a variable of type double. double* means a pointer to a double variable. double** means a pointer to a pointer to a double variable. In the case of the function you posted, it is used to create a sort of two-dimensional array of doubles. That is, a pointer to an array of double pointers, … Read more
It means that es3.c does not define a main function, and you are attempting to create an executable out of it. An executable needs to have an entry point, thereby the linker complains. To compile only to an object file, use the -c option: The above compiles es3.c to an object file, then compiles a file main.c that would contain the main function, and the linker merges es3.o and main.o into … Read more
There is no difference unless you write something weird like In the first case, the assignment will be to a temporary, and the overall effect will be v1 += v2. In the second case, the assignment will be to v1, so the overall effect will be v1 = v3. In the third case, the assignment won’t be allowed. … Read more
The problem is that buttonClickedEvent is a member function and you need a pointer to member in order to invoke it. Try this: And then when you invoke it, you need an object of type MyClass to do so, for example this: http://www.codeguru.com/cpp/cpp/article.php/c17401/C-Tutorial-PointertoMember-Function.htm
C++03 3.10/1 says: “Every expression is either an lvalue or an rvalue.” It’s important to remember that lvalueness versus rvalueness is a property of expressions, not of objects. Lvalues name objects that persist beyond a single expression. For example, obj , *ptr , ptr[index] , and ++x are all lvalues. Rvalues are temporaries that evaporate at the end of the full-expression in which … Read more
Because python passes lists by reference This means that when you write “b=a” you’re saying that a and b are the same object, and that when you change b you change also a, and viceversa A way to copy a list by value: If the list contains objects and you want to copy them as … Read more
If you will place your definitions in this order then the code will be compiled The definition of function doSomething requires the complete definition of class Ball because it access its data member. In your code example module Player.cpp has no access to the definition of class Ball so the compiler issues an error.