TUTORIAL · STEP 4 OF 7

Structs and enums

The public fields of a struct become properties, and every member of an enum is there by name.

new Module.Point() creates a Point, whose x and y read and write like any property. step takes the point by value, so C++ works on a copy and returns a new point.

The members of enum class Direction are Module.Direction.North, Module.Direction.East and so on. They pass straight into C++, and a member that comes back is the same object, so === compares them.

Only public members bind; whatever is private stays inside C++.

Try it

Add Direction turnLeft(Direction direction); and walk the square the other way round.

#pragma once
 
#include <string>
 
// Public fields of a struct read and write like properties.
struct Point {
    double x;
    double y;
};
 
// Members arrive as Module.Direction.North, .East and so on.
enum class Direction { North, East, South, West };
 
Point step(Point point, Direction direction, double distance);
Direction turnRight(Direction direction);
std::string nameOf(Direction direction);
 
 
#pragma once

#include <string>

// Public fields of a struct read and write like properties.
struct Point {
    double x;
    double y;
};

// Members arrive as Module.Direction.North, .East and so on.
enum class Direction { North, East, South, West };

Point step(Point point, Direction direction, double distance);
Direction turnRight(Direction direction);
std::string nameOf(Direction direction);

Runs without a compile until you edit the C++.

Console

Press Run, or Ctrl+Enter, to run main.js.