Assigning value of PlayGame() to bLevelComplete also runs PlayGame()...?

[LiquidNext]

Okay I’m just having a bit of a weird time trying to understand how this works. We went from this:

int main ()
{
    while (true)
    {
        PlayGame();
        std::cin.clear();
        std::cin.ignore();
    }

    return 0;
} 

to this:

int main ()
{
    while (true)
    {
        bool LevelComplete = PlayGame();
        std::cin.clear();
        std::cin.ignore();
    }

    return 0;
} 

My question is, does the line “bool LevelComplete = PlayGame();” not only assign the bool return value of PlayGame() to Level Complete, but also run the PlayGame() function…? I would’ve assumed it would only assign one value to the other and not also run the PlayGame function…but apparently it does. I just want to be clear as to what’s going on here.

[Aryan_Kumar]

You are right. The PlayGame() function runs, and the return value of the function gets assigned to LevelComplete.

[Bryan_Apostol]

Came here to ask this, as this wasn’t really explained.

I guess c++ has evolved this way because programmers have been employing it as a programming “shortcut” or technique?

Out of curiosity, is there a way to override this behaviour, if you just want to initialize variables to a function, but dont want the function to run at that time?

[DanM]

@Bryan_Apostol

because programmers have been employing it as a programming “shortcut” or technique?

This is how functions are meant to be used. You call them and they (potentially) return values. e.g.

int square(int n)
{
    return n * n;
}
int main()
{
    int value = square(2); //call square with 2, returns 4, value == 4
    value = square(5); // value now holds 25
}

@Bryan_Apostol

if you just want to initialize variables to a function

To be clear, that code isn’t being initialised to a function. It 's being initialised to what the function returns.

@Bryan_Apostol

Out of curiosity, is there a way to override this behaviour

It’s a completely different syntax. Such usage is not beginner level and more advanced. I’m curious as to why you want to do that.

[AbsorbingSheath]

I was curious about this question too.
You can check how code is executing using this site:
http://www.pythontutor.com/visualize.html#mode=edit
I have simplified code that was provided on the course and checked how exactly while loop is executed (you can also check it just not forget to select C++ language in the editor)

include

bool PlayGame()

{

// Declare 3 number code

int CodeA = 4;

int CodeB = 5;



//Store Player's Guesses

int GuessA =5; 

int GuessB =6;



//Check whether conditions are met

if (CodeA == CodeB && CodeB == GuessB)

{

    std::cout<< "You Win!\n";

    return true;

}



else 

{

    std::cout<<"You Lose!\n";

    return false;

} 

int main()

{ while(true)

{

bool bLevelComplete = PlayGame();

}

return 0;

}