Sizeof() on a C++ array works in one function, but not in the other

Question

I\'m trying to learn more about arrays since I\'m new to programming. So I was playing with different parts of code and was trying to learn about three things, sizeof(

Answer 1

This

void arrayprint(int inarray[])

Is equivalent to this:

void arrayprint(int *inarray)

So you are getting the size of an int pointer on your machine. Even if your question is about C++ and your function looks a bit different, it boils down to this C FAQ entry.

So, inside main n_array is actually a true honest array. But when passed to a function, it "decays" into a pointer. And there's no way to know the real size. All you can do is pass additional arguments to your function.

void arrayprint(int inarray[], int len)
{
    for (int n_i = 0 ; n_i < len; n_i++)
    /* .... */

And call it like this:

arrayprint(n_array, sizeof(n_array) / sizeof(n_array[0]));

Of course, the real solution would be to use vectors since you're using C++. But I wouldn't know much about C++.