How to Allocate an Array and Use a Constructor in C++?

How can I allocate an array and then use a constructor to initialize its elements in C++?

int *arr = new int[n]; for(int i = 0; i < n; i++) { arr[i] = i + 1; }

In C++, allocating an array dynamically and initializing its elements using a constructor can be efficiently achieved using the `new` operator. This approach allows you to create arrays of classes or primitive types, providing flexibility in object creation and management of resources.

class MyClass {
public:
    int value;
    MyClass(int v) : value(v) {}
};  

int n = 5;
MyClass *arr = new MyClass[n];
for (int i = 0; i < n; i++) {
    new(&arr[i]) MyClass(i + 1); // placement new to call constructor
}

Causes

• For dynamically sized arrays, static allocation is insufficient, requiring `new` for memory management.
• Constructors must be properly called to ensure correct initialization of classes in the array.

Solutions

• Utilize the `new` operator for dynamic memory allocation.
• If you are working with objects of a class, ensure you are using constructor syntax appropriately while allocating memory.
• Always pair `new` with `delete` to avoid memory leaks.

Mistake: Forgetting to call the constructor for each element in an array of objects.

Solution: Use the placement new syntax to explicitly call the constructor for each array element.

Mistake: Not deleting the allocated array resulting in memory leaks.

Solution: Always use `delete[]` to free dynamically allocated arrays.