Passing array by reference

[Bad Request]

Hello, everyone Im writing a simple program where the user will fill an array of integers. The array is then passed to a sort function that I'm writing. Heres the function prototype and function call.

  //prototype:
  void sortArray(int sizeOfArray, int &myArray);
  
  //function call in main()
  sortArray(sizeOfArray, &myArray)

When compiling I'm getting these errors:
1) error: invalid initialization of non-const reference of type 'int&' from an rvalue of type 'int (*)[(((sizetype)(((ssizetype)sizeOfArray) + -1)) + 1)]'|

2)error: in passing argument 2 of 'void sortArray(int, int&)'|

I've tried to search for a solution but all changes I've made only seemed to create more errors.

Any help would be greatly appreciated, thanks!

[MiiNiPaa]

In your prototype you declared my array as a reference to single int. But you are trying to pass a pointer to int. You probably want to declare myArray as pointer.

[Bad Request]

Update: I placed brackets after declaring int &myArray[] in the function protoype and was able to bring it down to only one error.

//function prototype 
void sortArray(int sizeOfArray, int &myArray[]);
//function call in main()
sortArray(sizeOfArray, &myArray);

results in the following error:
1)error: declaration of 'myArray' as array of references|

[MiiNiPaa]

Because you have declared an aray of references and this is illegal. Also you are still passing pointer and not array itself.
Correct way is to do:

//Note that you have to provide array dimensions here
void sortArray(int sizeOfArray, int (&myArray)[5])

[andywestken]

If you use an array reference you need to specify the size, as shown in MiiNiPaa's example. For that reason you can drop the sizeOfArray param.

void sortArrayOf5(int (&myArray)[5]);

If you want your function to handle different size arrays you will need to either use a pointer

void sortArray(int sizeOfArray, int* myArray)

or

void sortArray(int sizeOfArray, int myArray[]) // here [] means a pointer!!

OR make the function a template

template<int SizeOfArray>
void sortArray(int (&myArray)[SizeOfArray])

If you are using a lot of different sizes of array, the template aproach could lead to code bloat. So could implement the template version using the pointer version.

Andy

[Bad Request]

Understand. Ill make the corrections suggested. I do have a question though. The size of the array is not known at compile time. I assume that something like void sortArray(int (&myArray)[sizeOfArray]) is illegal. Is there another way of passing the array size to the function? Or should I just declare a constant that holds the array size?

//constant declaration
const int MAX_VAL = 100;
//function prototype
void sortArray(int (&myArray)[MAX_VAL])

Then write a check to make sure that the user stays under MAX_VAL?

[MiiNiPaa]

WHy do you desperately want to pass builtin array by reference? Are there some problems with decay to pointer or something?

[Bad Request]

Thanks andywestken. Didn't see your post before I wrote mine. That answered a lot of my questions!