#include <iostream>

using namespace std;

// Arrays are implicitly passed by reference.
// No size is given, but the array is NOT strechy!
// You just have to know how big the array is.

void foo(int data[]) {
    data[2] = 666;
}

int main() {
    int a[] = {11,22,33,44,55};
    foo(a);
    for (int i=0; i<5; i++)
    	cout << a[i] << ' ';		// You have to do it one-by-one
    cout << '\n';
    return 0;
}