DATA STRUCTURE AND ALGORITHM (Array)

 ARRAY

An Array is a collection of similar data items stored at contiguous memory locations and elements can be accessed randomly using indices of an array. 

Array

Array declaration by specifying size:

// Array declaration by specifying size

int array1[20];

// We can also declare an array of user specified size

int n = 20;

int array2[n];

Array declaration by initializing elements:

// Array declaration by initializing elements

int array[] = { 10, 20, 30, 40 }

Array declaration by specifying size and initializing elements:

// Array declaration by specifying size and initializing

// elements

int array[6] = { 10, 20, 30, 40 }

Advantages of an Array in C++: 

1. Random access of elements using array index.
2. Use of less line of code as it creates a single array of multiple elements.
3. Easy access to all the elements.
4. Traversal through the array becomes easy using a single loop.
5. Sorting becomes easy as it can be accomplished by writing less line of code.

Disadvantages of an Array in C++: 

1. Allows a fixed number of elements to be entered which is decided at the time of declaration. Unlike a linked list, an array in C is not dynamic.
2. Insertion and deletion of elements can be costly since the elements are needed to be managed in accordance with the new memory allocation.

A sample C++ program:

#include <iostream>

using namespace std;

 

int main()

{

    int arr[5];

    arr[0] = 15;

    arr[2] = -1;

 

    // this is same as arr[1] = 12

    arr[5 / 4] = 12;

    arr[3] = arr[0];

 

    cout << arr[0] << " " << arr[1] << " " << arr[2] << " "

         << arr[3];

 

    return 0;

}

Output:

15 12 -1 15

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