In modern browsers, you can use the let or const keywords to create a block-scoped variable: for (let i = 0; i < results.length; i++) { let marker = results[i]; google.maps.event.addListener(marker, ‘click’, () => change_selection(i)); } In older browsers, you need to create a separate scope that saves the variable in its current state by … Read more
For the second part of your question, see the array page of the manual, which states (quoting) : Array assignment always involves value copying. Use the reference operator to copy an array by reference. And the given example : <?php $arr1 = array(2, 3); $arr2 = $arr1; $arr2[] = 4; // $arr2 is changed, // … Read more
It doesn’t quite work that way in Python. Python passes references to objects. Inside your function you have an object — You’re free to mutate that object (if possible). However, integers are immutable. One workaround is to pass the integer in a container which can be mutated: def change(x): x[0] = 3 x = [1] … Read more
Types of Things in Swift The rule is: Class instances are reference types (i.e. your reference to a class instance is effectively a pointer) Functions are reference types Everything else is a value type; “everything else” simply means instances of structs and instances of enums, because that’s all there is in Swift. Arrays and strings … Read more
I think much confusion is generated by not communicating what is meant by passed by reference. When some people say pass by reference they usually mean not the argument itself, but rather the object being referenced. Some other say that pass by reference means that the object can’t be changed in the callee. Example: struct … Read more
It used to be generally recommended best practice1 to use pass by const ref for all types, except for builtin types (char, int, double, etc.), for iterators and for function objects (lambdas, classes deriving from std::*_function). This was especially true before the existence of move semantics. The reason is simple: if you passed by value, … Read more
Objects aren’t passed at all. By default, the argument is evaluated and its value is passed, by value, as the initial value of the parameter of the method you’re calling. Now the important point is that the value is a reference for reference types – a way of getting to an object (or null). Changes … Read more
When you compile a number literal in Java and assign it to a Integer (capital I) the compiler emits: Integer b2 =Integer.valueOf(127) This line of code is also generated when you use autoboxing. valueOf is implemented such that certain numbers are “pooled”, and it returns the same instance for values smaller than 128. From the … Read more
You need to pass in a pointer to a pointer if you want to do this. void barPush(BarList ** list,Bar * bar) { if (list == NULL) return; // need to pass in the pointer to your pointer to your list. // if there is no move to add, then we are done if (bar … Read more
Rules of thumb for C++11: Pass by value, except when you do not need ownership of the object and a simple alias will do, in which case you pass by const reference, you must mutate the object, in which case, use pass by a non-const lvalue reference, you pass objects of derived classes as base … Read more