Dynamic Arrays

• Definition:
  A dynamic array is a data structure that allows you to resize the array during runtime.
• Memory Allocation:
  Dynamic arrays are allocated memory on the heap, allowing them to grow or shrink as needed.
• Flexibility:
  Unlike static arrays, dynamic arrays can change their size dynamically, making them more versatile in handling varying amounts of data.
• Efficiency:
  Dynamic arrays offer better efficiency in terms of memory usage, as they allocate only the required amount of memory.
• Access Time:
  Access time to elements in a dynamic array is constant, similar to static arrays.
• Dynamic Array vs. Linked List:
  Dynamic arrays provide better random access time compared to linked lists, but they may not perform as well for insertions and deletions in the middle.
• Array Doubling:
  Common implementation involves doubling the array size when it reaches capacity, ensuring amortized constant time for append operations.
• Example Program in C:
Program.c
#include <stdio.h> #include <stdlib.h> int main() { // Declare a dynamic array of integers int *dynamicArray; // Allocate memory for an initial size (e.g., 5 elements) dynamicArray = (int *)malloc(5 * sizeof(int)); if (dynamicArray == NULL) { printf(“Memory allocation failed.\n”); return 1; // Exit with an error code } // Assign values to the dynamic array for (int i = 0; i < 5; i++) { dynamicArray[i] = i * 2; } // Print the elements of the dynamic array printf(“Dynamic Array Elements: “); for (int i = 0; i < 5; i++) { printf(“%d “, dynamicArray[i]); } // Resize the dynamic array (e.g., double the size) dynamicArray = (int *)realloc(dynamicArray, 10 * sizeof(int)); if (dynamicArray == NULL) { printf(“Memory reallocation failed.\n”); return 1; // Exit with an error code } // Assign values to the additional elements for (int i = 5; i < 10; i++) { dynamicArray[i] = i * 2; } // Print the updated dynamic array printf(“\nUpdated Dynamic Array Elements: “); for (int i = 0; i < 10; i++) { printf(“%d “, dynamicArray[i]); } // Free the allocated memory free(dynamicArray); return 0; // Exit successfully }

Output:
Dynamic Array Elements: 0 2 4 6 8
Updated Dynamic Array Elements: 0 2 4 6 8 10 12 14 16 18