DS-lect2.pdf data structure in c ++ engineering

Data Structures
and
Algorithms
Assoc. Prof.
Ahmed Moustafa Elmahalawy
Computer Science and Engineering Department
Faculty of Electronics Engineering
Menoufia University

‫المحاضرة‬ ‫ميثاق‬
‫المتبادل‬ ‫االحترام‬ ‫المحمول‬ ‫إغالق‬
‫الهدف‬ ‫تحديد‬ ‫المشاركة‬ ‫بالوق‬ ‫االلتزام‬
‫ت‬

Lecture 2
Array Data Structures

Data Structures and Algorithms Lecture 2: Array data Structures
Contents:-
1. Defining and Declaring Arrays
2. Operations on Arrays
3. Advantages and Disadvantages
4. Example Code

Arrays are one of the fundamental data
structures in programming. They are used
to store collections of elements of the
same type in contiguous memory
locations.
In C++, arrays are straightforward and
versatile, providing efficient indexing and
easy management of collections.

1. Defining and Declaring Arrays
In C++, arrays are defined by
specifying the type of their elements and
the number of elements they can hold.
1.1. Single-Dimensional Arrays
1.2. Multi-Dimensional Arrays

1.1. Single-Dimensional Arrays
A single-dimensional array is a list of
elements stored in a contiguous block of
memory.
- Syntax
- Example
- Initialization
- Accessing Elements

*Syntax:
type arrayName[arraySize];
*Example:
int numbers[5];
// An array of 5 integers
*Initialization:
int numbers[5] = {1, 2, 3, 4, 5};
// Array with initialized values

*Accessing Elements
numbers[0] = 10;
// Assigns 10 to the first element
int x = numbers[1];
// Retrieves the second element

1.2. Multi-Dimensional Arrays
Multi-dimensional arrays are arrays of
arrays.
The most common is the two-
dimensional array, which can be
visualized as a matrix.
- Syntax
- Example
- Initialization
- Accessing Elements

*Syntax
type arrayName[rowSize][columnSize];
*Example
int matrix[3][4]; // A 3x4 matrix of integers

*Initialization
int matrix[3][4] = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12}
};

*Accessing Elements
matrix[0][0] = 1;
// Assigns 1 to the first element of the first
row
int y = matrix[1][2];
// Retrieves the element in the second
row, third column

2. Operations on Arrays
2.1. Traversal
2.2. Insertion
2.3. Deletion
2.4. Searching

2.1. Traversal
To traverse an array means to visit each
element in the array, usually to perform
some operation.
Example:
// Traversing a single-dimensional array
for (int i = 0; i < 5; ++i) {
cout << numbers[i] << " ";
}
cout << endl;

// Traversing a two-dimensional array
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 4; ++j) {
cout << matrix[i][j] << " ";
}
cout << endl;
}

2.2. Insertion
Inserting an element in an array
typically involves placing the element at a
specific position.

Example
// Inserting in a single-dimensional array
(if the array has space)
int arr[6] = {1, 2, 3, 4, 5};
int position = 2;
// Position where 10 should be inserted
int value = 10;
for (int i = 5; i >= position; --i) {
arr[i] = arr[i - 1];}
arr[position] = value;

// Inserting in a two-dimensional array (if the array
has space)
#include<iostream>
using namespace std; main( )
{ int s[2][2]; int i, j; cout<<"n2D Array
Input:n"; for(i=0;i<2;i++)
{ for(j=0;j<2;j++)
{ cout<<"ns["<<i<<"]["<<j<<"]= ";
cin>>s[i][j]; } } cout<<"nThe
2-D Array is:n"; for(i=0;i<2;i++)
{ for(j=0;j<2;j++)
{
cout<<"t"<<s[i][j]; } cout<<endl; }}

2.3. Deletion
Deleting an element from an array
involves removing the element and
shifting subsequent elements.

Example
// Deleting from a single-
dimensional array
int arr[6] = {1, 2, 3, 4, 5, 6};
int position = 2;
// Position of the element to be deleted
for (int i = position; i < 5; ++i) {
arr[i] = arr[i + 1];
}

Exercise
Show how to delete a value
from a two-dimensional array

Example (Linear Search):
bool linearSearch(int arr[], int size, int
key) {
for (int i = 0; i < size; ++i) {
if (arr[i] == key) {
return true;
}
}
return false;

Example (Binary Search):
bool binarySearch(int arr[], int size, int key) {
int left = 0, right = size - 1;
while (left <= right) {
int mid = left + (right - left) / 2;
if (arr[mid] == key) {
return true; }
if (arr[mid] < key) {
left = mid + 1; } else {
right = mid - 1; } }
return false; }

3. Advantages and Disadvantages
3.1. Advantages
- Efficient Access: Direct indexing allows
quick access to elements.
- Simplicity: Easy to implement and use
for fixed-size data collections.

3.2. Disadvantages
- Fixed Size: Size must be defined at
compile-time and cannot be changed
dynamically.
- Memory Allocation: Allocates memory
for the entire array, which may lead to
wasted space if not fully used.
- Insertion/Deletion Overhead: Expensive
operations if not performed at the end
of the array.

4. Example Code
Here's a complete C++ program
demonstrating array operations:
#include <iostream>
using namespace std;
int main() {
// Single-dimensional array
int numbers[5] = {1, 2, 3, 4, 5};

// Traversal
cout << "Single-dimensional array
elements:" << endl;
for (int i = 0; i < 5; ++i) {
cout << numbers[i] << " ";
}
cout << endl;

// Two-dimensional array
int matrix[3][4] = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12}
};

// Traversal
cout << "Two-dimensional array
elements:" << endl;
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 4; ++j) {
cout << matrix[i][j] << " ";
}
cout << endl;
}
return 0; }

Exercises
1- Find the Minimum and Maximum
Element in an Array
2- Array Reverse
3- Write a Program to Cyclically Rotate
an Array by One
4- Find the Factorial of a Large Number
5- First missing positive number
Computer Programming Lecture 2: Array Data Structure

DS-lect2.pdf data structure in c ++ engineering

More Related Content

Similar to DS-lect2.pdf data structure in c ++ engineering

Recently uploaded

DS-lect2.pdf data structure in c ++ engineering