C++ Dynamic Memory Allocation: Creating an array of objects with new operator

Last update on April 12 2025 12:57:51 (UTC/GMT +8 hours)

6. Dynamically Create an Array of Objects Using New

Write a C++ program to dynamically create an array of objects using the new operator.

Sample Solution:

C Code:

#include <iostream>  // Including the Input/Output Stream Library

class MyClass {  // Declaration of a class named MyClass
public:
  void displayMessage() {  // Public member function within the class MyClass
    std::cout << "Dynamic object!" << std::endl;  // Outputting a message
  }
};

int main() {
  // Get the size of the array from the user
  int size;  // Declaring a variable to store the size of the array
  std::cout << "Input the size of the array: ";  // Prompting the user to enter the size of the array
  std::cin >> size;  // Reading the size of the array entered by the user

  // Create a dynamic array of MyClass objects
  MyClass * dynamicArray = new MyClass[size];  // Dynamically allocating memory for an array of MyClass objects of 'size'

  // Access and use the objects in the dynamic array
  for (int i = 0; i < size; i++) {  // Looping through each element of the dynamic array
    dynamicArray[i].displayMessage();  // Accessing and invoking the displayMessage function for each MyClass object
  }

  // Deallocate the dynamic array
  delete[] dynamicArray;  // Deallocating the memory occupied by the dynamic array

  return 0;  // Returning 0 to indicate successful execution of the program
}

Sample Output:

Input the size of the array: 10
Dynamic object!
Dynamic object!
Dynamic object!
Dynamic object!
Dynamic object!
Dynamic object!
Dynamic object!
Dynamic object!
Dynamic object!
Dynamic object!

Explanation:

In the above exercise,

• We define a class called MyClass with a member function displayMessage() that outputs a message.
• Inside the main() function, prompt the user to input the array size using std::cin. We store the size in the size variable.
• We then use the new operator to dynamically create an array of MyClass objects and assign its address to a pointer called dynamicArray. This dynamically created array resides in the heap memory.
• Next we use a for loop to access and use each object in the dynamic array. In this example, we call the displayMessage() member function of each object.
• Finally, we deallocate the dynamically created array using the delete[] operator to free the memory occupied by the array.

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C++ program to define a class for a book and then dynamically allocate an array of book objects, initializing and printing their details.
• Write a C++ program that creates a dynamic array of objects of a class representing a point in 2D space and prints their coordinates.
• Write a C++ program to dynamically allocate an array of objects of a class (e.g., Employee) and input values for each object from the user.
• Write a C++ program that uses new to create an array of objects for a class with a parameterized constructor, then displays the array contents.

CPP Code Editor:

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