C++ Arrays

C++ Arrays

arrays in C++ are a fundamental concept used to store multiple values of the same type in a single variable. Here’s a comprehensive overview:

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Declaration and Initialization

1. Declaration: To declare an array in C++, you specify the type of its elements and the number of elements (size):
   int numbers[5]; // Declares an array of 5 integers

2. Initialization: You can initialize an array at the time of declaration:
   int numbers[5] = {1, 2, 3, 4, 5}; // Initializes all elements


   If you don’t initialize all elements, the remaining elements will be set to zero (for fundamental types):

   int numbers[5] = {1, 2}; // numbers[0] = 1, numbers[1] = 2, numbers[2] to numbers[4] = 0


   You can also leave the size unspecified when you provide the initialization:

   int numbers[] = {1, 2, 3, 4, 5}; // Compiler determines the size (5 in this case)


Accessing Elements

You can access array elements using the index, which starts from 0:

Iterating Through Arrays

You can use loops to iterate through array elements:

Multidimensional Arrays

C++ supports multidimensional arrays. Here’s how you declare and initialize a 2D array:

Common Operations

1. Finding the Size:

   To find the number of elements in a statically declared array:

   int size = sizeof(numbers) / sizeof(numbers[0]);

2. Copying Arrays:

   Arrays cannot be directly copied using the assignment operator. You need to use a loop or std::copy from the <algorithm> header:

   int source[5] = {1, 2, 3, 4, 5};

   int destination[5];

   // Using a loop


   for(int i = 0; i < 5; ++i) {

   destination[i] = source[i];

   }

   // Using std::copy


   std::copy(std::begin(source), std::end(source), std::begin(destination));

3. Passing Arrays to Functions:

   Arrays are passed to functions by reference (the pointer to the first element is passed). Here’s how you define and call a function that takes an array:

   void printArray(int arr[], int size) {


   for(int i = 0; i < size; ++i) {

   std::cout << arr[i] << " ";


   }

   }


   int main() {


   int numbers[] = {1, 2, 3, 4, 5};

   printArray(numbers, 5);

   return 0;

   }


Dynamic Arrays

For dynamically-sized arrays, C++ provides the std::vector from the Standard Library, which offers a more flexible and safer alternative to C-style arrays. Here’s a quick example:

Summary

• Arrays in C++ are a collection of elements of the same type stored in contiguous memory locations.
• You can declare, initialize, and access elements of arrays using indices.
• Use loops to iterate over arrays.
• C++ supports multidimensional arrays.
• For dynamic arrays, consider using std::vector for better safety and functionality.