New and Delete operator in C++

What is a C++ Delete Operator?

The C++ delete operator is used to deallocate memory that was previously allocated using the new operator. When dynamically allocated memory is no longer needed, the delete operator frees up the memory so that it can be reused by other parts of the program or by the operating system. This helps prevent memory leaks and ensures efficient memory usage in C++ programs. It is important to pair each new operator with a corresponding delete operator to avoid memory leaks and potential program instability.

Syntax for delete operator

delete pointerVariable

Ex: delete p;

C++ code for delete operator

#include <bits/stdc++.h>

using namespace std;

int main() {

  // pointer initialized
  int * Ninjas = new int(5);

  //value printed
  cout << * Ninjas << endl;

  //pointer deleted
  delete Ninjas;
}

Output:

5

You can try and compile with the help of online c++ compiler.

Differences between New and Delete Operators in C++

C++ code for arrays using new and delete

#include <bits/stdc++.h>

using namespace std;

int main() {
  int * Ninjas = new int[5];
  for (int i = 0; i < 5; i++) {
    *(Ninjas + i) = i;
  }
  for (int i = 0; i < 5; i++) {
    cout << * (Ninjas + i) << " ";
  }
  delete[] Ninjas;
}

Output:

0 1 2 3 4 

C++ code for objects using new and delete

#include <bits/stdc++.h>

using namespace std;

class Ninjas {
  public:

    //Constructor
    Ninjas() {
      cout << "inside Ninjas constructor" << endl;
    }

    //Destructor
    ~Ninjas() {
      cout << "inside Ninjas destructor" << endl;
    }
};

int main() {
  //Dynamic memory Allocation to array of objects of type Ninjas
  Ninjas * s = new Ninjas[5];

  // Delete array which was created dynamically
  delete[] s;

  return 0;
}

Output:

inside Ninjas constructor
inside Ninjas constructor
inside Ninjas constructor
inside Ninjas constructor
inside Ninjas constructor
inside Ninjas destructor
inside Ninjas destructor
inside Ninjas destructor
inside Ninjas destructor
inside Ninjas destructor

Also check out this article - Pair in C++

Frequently Asked Questions

What is the new and delete operator in C++?

In C++, the new operator dynamically allocates memory for objects or arrays on the heap, while the delete operator deallocates memory previously allocated with new, preventing memory leaks.

What is new and delete in C++ constructor?

In C++, new is used in combination with constructors to dynamically allocate memory for objects and initialize them, while delete is used to destroy objects and deallocate memory.

How to delete an operator in C++?

In C++, the delete operator is used to deallocate dynamically allocated memory. It is followed by the pointer variable pointing to the memory to be deallocated. For example: delete ptr;

What is new int in C++?

In C++, new int dynamically allocates memory on the heap to store an integer. It returns a pointer to the allocated memory, allowing for dynamic memory allocation for integer values.

Conclusion

This article is about the New and Delete operator in C++. These operators in C++ provide powerful mechanisms for dynamic memory allocation and deallocation. Proper understanding and usage of these operators are crucial for effective memory management, preventing memory leaks and ensuring efficient utilization of system resources.

Recommended Readings:

• Dynamic Binding in C++
• C++ Interview Questions

It’s excellent to apply dynamic memory allocation because of its flexibility and different usages that are primarily based on programmer requirements, as defined within the above article. So, there are instances wherein the memory desires can most effectively be decided at runtime. For example, the memory desires rely upon the programmer's input. In such varieties of instances, programmers can use dynamic memory allocation.

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