How to Dynamically Resize a C++ Array? Last Updated : 06 Mar, 2024 Summarize Comments Improve Suggest changes Share Like Article Like Report In C++, an array is a collection of elements of the same type placed in contiguous memory locations. In this article, we will learn how to dynamically resize an array in C++. Example: Input: myArray = {10, 20, 30, 40, 50};Output:Resized array: 10 20 30 40 50 0 0 0 0 0 Resizing a Dynamic Array in C++ In C++, the size of an array is static, but we can also create a dynamic array in C++ using the new and delete operators. However, there is no direct method to specifically resize these dynamic arrays. To do that, we have to allocate a new memory block of the new size, copy all the elements of the previous array, and then delete the previous array. ApproachCreate a new array with the desired size.Use the std::copy function from the <algorithm> library to copy the elements from the old array to the new one.When all the elements are copied, delete the old array to free up the memory it was using.Finally, assign the pointer of the old array to the new array.C++ Program to Resize a Dynamic Array in C++The below example demonstrates how we can dynamically resize an array in C++. C++ // C++ Program to illustrate how to dynamically resize an // array #include <algorithm> #include <iostream> using namespace std; int main() { // Initialize an int array int* arr = new int[5]{ 10, 20, 30, 40, 50 }; int size = 5; cout << "Original array: "; for (int i = 0; i < size; i++) { cout << arr[i] << " "; } cout << endl; // create new array of the new size int newSize = 10; int* newArr = new int[newSize]; // copy all the elements copy(arr, arr + size, newArr); // deallocate the previous array and assing the pointer // to the previous array to the new one delete[] arr; arr = newArr; // printing array cout << "Resized array: "; for (int i = 0; i < newSize; i++) { cout << arr[i] << " "; } cout << endl; return 0; } OutputOriginal array: 10 20 30 40 50 Resized array: 10 20 30 40 50 0 0 0 0 0 Time Complexity: O(N)Auxiliary Space: O(N), here N is the new size after resizing Note: The above method is not recommended if you want to perform frequent resizing because it has high time complexity. For such cases use std::vector which handles resizing automatically. Comment More infoAdvertise with us Next Article How to Dynamically Resize a C++ Array? P pantharshx9d9 Follow Improve Article Tags : C++ Programs C++ cpp-array Dynamic Memory Allocation CPP Examples +1 More Practice Tags : CPP Similar Reads C++ Programming Language C++ is a computer programming language developed by Bjarne Stroustrup as an extension of the C language. It is known for is fast speed, low level memory management and is often taught as first programming language. It provides:Hands-on application of different programming concepts.Similar syntax to 5 min read Non-linear Components In electrical circuits, Non-linear Components are electronic devices that need an external power source to operate actively. Non-Linear Components are those that are changed with respect to the voltage and current. Elements that do not follow ohm's law are called Non-linear Components. Non-linear Co 11 min read Spring Boot Tutorial Spring Boot is a Java framework that makes it easier to create and run Java applications. It simplifies the configuration and setup process, allowing developers to focus more on writing code for their applications. This Spring Boot Tutorial is a comprehensive guide that covers both basic and advance 10 min read Object Oriented Programming in C++ Object Oriented Programming - As the name suggests uses objects in programming. Object-oriented programming aims to implement real-world entities like inheritance, hiding, polymorphism, etc. in programming. The main aim of OOP is to bind together the data and the functions that operate on them so th 5 min read Class Diagram | Unified Modeling Language (UML) A UML class diagram is a visual tool that represents the structure of a system by showing its classes, attributes, methods, and the relationships between them. It helps everyone involved in a projectâlike developers and designersâunderstand how the system is organized and how its components interact 12 min read 3-Phase Inverter An inverter is a fundamental electrical device designed primarily for the conversion of direct current into alternating current . This versatile device , also known as a variable frequency drive , plays a vital role in a wide range of applications , including variable frequency drives and high power 13 min read Backpropagation in Neural Network Back Propagation is also known as "Backward Propagation of Errors" is a method used to train neural network . Its goal is to reduce the difference between the modelâs predicted output and the actual output by adjusting the weights and biases in the network.It works iteratively to adjust weights and 9 min read 30 OOPs Interview Questions and Answers [2025 Updated] Object-oriented programming, or OOPs, is a programming paradigm that implements the concept of objects in the program. It aims to provide an easier solution to real-world problems by implementing real-world entities such as inheritance, abstraction, polymorphism, etc. in programming. OOPs concept is 15 min read What is Vacuum Circuit Breaker? A vacuum circuit breaker is a type of breaker that utilizes a vacuum as the medium to extinguish electrical arcs. Within this circuit breaker, there is a vacuum interrupter that houses the stationary and mobile contacts in a permanently sealed enclosure. When the contacts are separated in a high vac 13 min read Polymorphism in Java Polymorphism in Java is one of the core concepts in object-oriented programming (OOP) that allows objects to behave differently based on their specific class type. The word polymorphism means having many forms, and it comes from the Greek words poly (many) and morph (forms), this means one entity ca 7 min read Like