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README.md |
Exercise: Pay with parameter passing
In this exercise we will look together at what happens when we change a reference parameter to a value or a const reference.
Let's look at this function
void Game::processEvents(InputState & inputState) {
auto event = canvas.pollEvent();
if (event && event.value().type == sf::Event::Closed) {
inputState.close = true;
return;
}
inputState.down = sf::Keyboard::isKeyPressed(sf::Keyboard::Key::Down);
inputState.up = sf::Keyboard::isKeyPressed(sf::Keyboard::Key::Up);
inputState.left = sf::Keyboard::isKeyPressed(sf::Keyboard::Key::Left);
inputState.right = sf::Keyboard::isKeyPressed(sf::Keyboard::Key::Right);
}
Exercise
-
Make
inputState
a value. What happens when you compile the code? Can you explain why? -
Now make it a
const
reference. What happens? Can you explain why? -
Revert it back to a non-const reference an make sure the code compile.