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How can I change an array using a function?

I am new to C ++ and I am facing a problem.
I am trying to write a blackjack game. I have a 52 array of "char" type with different cards and I want to shuffle it. I'm not sure how this is not a problem. I made a function called "ShuffleDeck" but it doesn't work, says it can't return an array. I also cannot reference the array. How should I do it? Here is the piece of code I'm talking about.

void ShuffleDeck(bool &rgCards[]) {
    for (int i = 1; i < 52; ++i) {
        //something
    }
    return rgCards[];
}

All help was appreciated.

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5 answers


You use std::vector

and shuffle the values ​​in it. It is preferable to pass it by reference to a function and work with the original vector.

It is not entirely clear from your snippet what you expect from it - you are passing the array bool

by reference, but returning it as int

with syntax rgCards[]

, which makes absolutely no sense in this context.



EDIT: as per Fred's comment - you can use random_shuffle

.

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From the code snippet you provided, it looks like you are trying to pass an array reference to ShuffleDeck()

. The C ++ syntax for an array reference is data-type (&)[N]

, where N

is the number of elements in the array. Change your function to

void ShuffleDeck( char (&rgCards)[52] ) { ... }

You can do it as a template function and calculate the length of the array



template<size_t N>
void ShuffleDeck( char (&rgCards)[N] ) { ... }

Finally, since you are using C ++, you should probably switch to using a container class such as std::array

or std::vector

rather than a C type array.

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You can also do this

void shuffle(int* deck, int size)
{
  for(int i =0; i < size; i++)
  {
    deck[i] = i;
  }
}

This shows that the array is indeed being passed as a pointer.

int deck[52];
shuffle(deck,52);
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To keep the code most similar to what you are writing, I'll just make minimal fixes: note that &

it is not required and the index must start at 0.

void ShuffleDeck(bool rgCards[]) {
    for (int i = 0; i < 52; ++i) {
        //something
    }
}

any change you make to rgCards [i] will be available after calling ShuffleDeck

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Cleanest solution, IMO:

class Deck {
  char cards[52];
public:
  void Shuffle();
};

void Deck::Shuffle()
{
  // I can change cards here because both cards and Shuffle are members of Deck
}
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