How to Create a Dynamic Array in C++ Without STL Classes

2025-02-04

Creating a dynamic array in C++ without using STL classes like `std::vector` involves leveraging dynamic memory allocation, pointers, and pass-by-reference parameters. Below is a step-by-step guide with practical code examples to help you understand the process.

Step 1: Initialize Variables

Start by initializing a pointer to `nullptr` and a variable to track the size of the array.

#include <iostream>

int main() {
int* arr = nullptr;
int size = 0;
// Function calls will go here
return 0;
}

Step 2: Create a Function to Add Elements

Define a function that takes the new element, the size of the array, and the array pointer as parameters. This function will handle the dynamic resizing of the array.

void addElement(int newElement, int& size, int<em>& arr) {
// Create a new array with increased size
int</em> newArr = new int[size + 1];

// Copy elements from the old array to the new one
for (int i = 0; i < size; ++i) {
newArr[i] = arr[i];
}

// Add the new element at the end
newArr[size] = newElement;

// Free the memory of the old array
delete[] arr;

// Update the pointer and size
arr = newArr;
++size;
}

Step 3: Use the Function in `main`

Call the `addElement` function to dynamically add elements to the array.

int main() {
int* arr = nullptr;
int size = 0;

addElement(10, size, arr);
addElement(20, size, arr);
addElement(30, size, arr);

// Print the array
for (int i = 0; i < size; ++i) {
std::cout << arr[i] << " ";
}

// Free the final array
delete[] arr;
return 0;
}

Step 4: Output

The output will display the dynamically resized array:

10 20 30

What Undercode Say

Creating dynamic arrays in C++ without STL classes is a fundamental exercise in understanding memory management and pointers. By manually allocating and deallocating memory, you gain deeper insights into how data structures work under the hood. Here are some additional Linux and IT-related commands and concepts that complement this topic:

1. Memory Management in Linux: Use commands like `free -m` to monitor memory usage and `valgrind` to detect memory leaks in your C++ programs.
2. Pointers and References: Understanding pointers is crucial for low-level programming. Practice using `gdb` to debug pointer-related issues.
3. Dynamic Memory Allocation: Explore malloc, calloc, and `realloc` in C for similar functionality.
4. Array Manipulation: Use shell scripting to manipulate arrays in Linux. For example:

   arr=(10 20 30)
   arr+=("40")
   echo ${arr[@]}
   

5. Performance Optimization: Learn about memory fragmentation and how to optimize dynamic memory allocation for performance-critical applications.
6. Advanced C++ Features: Explore smart pointers (std::unique_ptr, std::shared_ptr) to automate memory management in modern C++.
7. Debugging Tools: Familiarize yourself with tools like `strace` and `ltrace` to trace system calls and library calls in Linux.
8. Scripting for Automation: Use Python or Bash scripts to automate repetitive tasks in IT environments.
9. Version Control: Use `git` to manage your codebase and collaborate with others.
10. Security Practices: Always sanitize inputs and validate memory allocations to prevent vulnerabilities like buffer overflows.

By mastering these concepts and tools, you can build robust and efficient applications while ensuring secure and maintainable code. For further reading, check out resources like GeeksforGeeks and cppreference.com.

References:

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