Return array in a function

c++ arrays pointers function return
Ismail Marmoush picture Ismail Marmoush · Aug 13, 2010 · Viewed 830.6k times · Source

I have an array int arr[5] that is passed to a function fillarr(int arr[]):

int fillarr(int arr[])
{
    for(...);
    return arr;
}
  1. How can I return that array?
  2. How will I use it, say I returned a pointer how am I going to access it?

Answer

Brent Writes Code picture Brent Writes Code · Aug 13, 2010

In this case, your array variable arr can actually also be treated as a pointer to the beginning of your array's block in memory, by an implicit conversion. This syntax that you're using:

int fillarr(int arr[])

Is kind of just syntactic sugar. You could really replace it with this and it would still work:

int fillarr(int* arr)

So in the same sense, what you want to return from your function is actually a pointer to the first element in the array:

int* fillarr(int arr[])

And you'll still be able to use it just like you would a normal array:

int main()
{
  int y[10];
  int *a = fillarr(y);
  cout << a[0] << endl;
}

Related questions

Passing a 2D array to a C++ function

I have a function which I want to take, as a parameter, a 2D array of variable size. So far I have this: void myFunction(double** myArray){ myArray[x][y] = 5; etc... } And I have declared an array elsewhere in my …

Read More
How to get the real and total length of char * (char array)?

For a char [], I can easily get its length by: char a[] = "aaaaa"; int length = sizeof(a)/sizeof(char); // length=6 However, I cannot do like this to get the length of a char * by: char *a = new char[10]; int length = …

Read More
Pointer-to-pointer dynamic two-dimensional array

First timer on this website, so here goes.. I'm a newbie to C++ and I'm currently working through the book "Data structures using C++ 2nd ed, of D.S. Malik". In the book Malik offers two ways of creating a …

Read More