the role of void and return keyword

Johnny Nguyen

Hi Guys!
When try to answer the questions to prepare for text, I got the question like this: Consider the C# method below. What happens if the keyword return is removed?

public void FireCannonBall()
{
   foreach ( GameObject ball on cannonBalls)
        {
           if (!ball.alive)
           {
                   ball.alive= true;
                   ball.position= cannon.position-ball.center;
                   ball.velocity= new Vector2((float)Math.Cos(cannon.rotation),(float)Math.sin(cannon.rotation))* 5.0f;
           return;
                }
        }
}

I my opinion,if the keyword return is removed, we will meet the error.This class is void class, so it is cannot return. we remove the keyword return,the compiler will not understand and do not return ball.velocity to float type.
Is that the right answer????

Could you please help me to find the correct answer for the question?

Regards
Jonny

2 Replies

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Jean Paul15y ago
Hi Johnny,

I would like to denote that removing return does not throw error.
The void methods shall also have return statement - this can be used to exit the method while middle of execution.

return is mandatory for non-void methods.

In the above case if return is removed, the loop should continue till all GameObject are processed and then the method will exit.

Regards,
Jean Paul
Vulpes15y ago
As the method has a return type of void, then the compiler won't complain if you don't use the 'return' keyword.

However, you should use the 'return' keyword if you want the method to return prematurely without running to the end.

This is what's apparently happening here. If a ball isn't 'alive' then after making it 'alive' and setting some properties, the method then returns. So, if you removed the 'return' statement, the foreach statement would proceed to look at the remaining balls in the cannonBalls collection. That may or may not be what you want.