Table of content

• Searching Algorithms
  • classification :
    • Linear Search
      • Code
      • Properties
      • Advantages
      • Disadvantage

Searching Algorithms

• searching is the process of finding an item with specified properties from a collection of items. The items may be stored as records in a database, simple data elements in arrays or they may be elements of other search spaces.

• There are certain ways of organizing the data that improves the searching process.

  Classification :

• Generally There are two categories of searching.

  • a)Sequential Search
  • b) Interval Search:
• The Example of Sequential Search is :-(Linear Search).
• The Example of Interval Search is :- (Binary Search).

Linear Search

• Start from the zero index of array and one by one compare Search Element(X) with each element of arr[].
• If Search Element(X) matches with an element of the arr[], return the index.
• If Search Element(X) doesn’t match with any of elements, then return -1.

Some More Example

Code

// C++ code to linearly search x in arr[]. If search ELement (x)
// is present then return its Index, otherwise
// return -1
#include <iostream>
using namespace std;

int search(int arr[], int n, int searchkey)
{

    for (int i = 0; i < n; i++)
        if (arr[i] == searchkey)
            return i;
    return -1;
}

// Driver code
int main()
{
    int arr[] = { 2, 3, 4, 10, 40 };
    int searchkey; // = 10;
    cin>> searchkey;
    int n = sizeof(arr) / sizeof(arr[0]);

    // Function call
    int result = search(arr, n, searchkey);
    (result == -1)
        ? cout << "Element is not present in array"
        : cout << "Element is present at index " << result;
    return 0;
}

Properties

• Time Complexity : O(n)
• Space Complexity : O(1)
• It has a very simple implementation.

Advantages

• The list does not need to sorted

Disadvantage

• Inversely, slow searching of big lists.

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