How to pass the array directely to a C++ constructor - c++

Question

So I wrote this C++ Class for storing an Array:
#include<bits/stdc++.h>
using namespace std;
class Array
{
private:
int size;
int *A = new int[size];
int length;
public:
Array(int arr[],int sz = 10)
{
length = sz;
size = 10;
for(int i=0;i<length;i++)
A[i] = arr[i];
}
~Array()
{
delete []A;
}
void Display();
void Insert(int index, int x);
};
void Array::Display()
{//code}
void Array::Insert(int index, int x)
{//code}
int main()
{
int a[3] = {1,2,3};
Array arr(a, 3);
arr.Display();
arr.Insert(1,4);
arr.Display();
}
This works fine. But in the main() function:
int main()
{
int a[3] = {1,2,3};
Array arr(a, 3);
arr.Display();
}
I am passing the pointer to the array a in the Class constructor.
Is there a way to pass the array like this?
Array arr({1,2,3}, 3);

Answer 1

You probably need to use something like this. But please note this code is still not optimal and it is usually much better to use std::vector or in some cases std::array.
#include <initializer_list>
class Array
{
private:
int *m_data = nullptr;
int m_size = 0;
int m_capacity = 0;
public:
Array(int arr[], int sz = 10) {
m_size = sz;
m_capacity = sz;
m_data = new int[m_capacity];
for(int i=0; i < m_size; i++) {
m_data[i] = arr[i];
}
}
Array(const std::initializer_list<int> &il) {
m_size = il.size();
m_capacity = il.size();
m_data = new int[m_capacity];
auto it = il.begin();
for (int i = 0; i < m_size; ++i) {
m_data[i] = *it;
++it;
}
}
~Array() {
delete [] m_data;
}
int size() const { return m_size; }
bool empty() const { return m_size == 0; }
int& operator[](int id) { return m_data[id]; }
int operator[](int id) const { return m_data[id]; }
};
#include <cstdio> // for printf
int main() {
Array arr({1,2,3});
printf(" %i \n",arr.size());
return 0;
}