Linear Search

In this tutorial, you will learn about the linear search. Likewise, you will discover working instances of linearsearch C, C++, Java, and Python.

What is Linear Search?

A LinearSearch is the most fundamental type of searching algorithm. A LinearSearch consecutively travels through your assortment (or data structure) searching for a coordinating value. All in all, it looks down a list, one item at a time, without jumping.

Consider it a method of finding your way in a phonebook. A LinearSearch is beginning toward the start, reading each name until you find what you’re searching for. n complexity terms this is an O(n) search – the time taken to search the list gets bigger at a similar rate as the list does.

Linear search is the least difficult searching algorithm that searches for an element in a list in consecutive order. We start toward one side and check each element until the desired element isn’t found.

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How Linear Search Works?

The accompanying steps are followed to search for an element k = 1 in the list underneath.

• 

1. Start from the primary element, compare k and every element x

• 

2. On the off chance that x == k, return the index.

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3. Else, return not found.

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Linear Search Algorithm

LinearSearch(array, key)
  for each item in the array
    if item == value
      return its index

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Python, Java, and C/C++ Examples

Python

# Linear Search in Python


def linearSearch(array, n, x):

    # Going through array sequencially
    for i in range(0, n):
        if (array[i] == x):
            return i
    return -1


array = [2, 4, 0, 1, 9]
x = 1
n = len(array)
result = linearSearch(array, n, x)
if(result == -1):
    print("Element not found")
else:
    print("Element found at index: ", result)

Java

// Linear Search in Java

class LinearSearch {
  public static int linearSearch(int array[], int x) {
  int n = array.length;

  // Going through array sequencially
  for (int i = 0; i < n; i++) {
    if (array[i] == x)
    return i;
  }
  return -1;
  }

  public static void main(String args[]) {
  int array[] = { 2, 4, 0, 1, 9 };
  int x = 1;

  int result = linearSearch(array, x);

  if (result == -1)
    System.out.print("Element not found");
  else
    System.out.print("Element found at index: " + result);
  }
}

C

// Linear Search in C

#include <stdio.h>

int search(int array[], int n, int x) {
  
  // Going through array sequencially
  for (int i = 0; i < n; i++)
    if (array[i] == x)
      return i;
  return -1;
}

int main() {
  int array[] = {2, 4, 0, 1, 9};
  int x = 1;
  int n = sizeof(array) / sizeof(array[0]);

  int result = search(array, n, x);

  (result == -1) ? printf("Element not found") : printf("Element found at index: %d", result);
}

C++

// Linear Search in C++

#include <iostream>
using namespace std;

int search(int array[], int n, int x) {

  // Going through array sequencially
  for (int i = 0; i < n; i++)
    if (array[i] == x)
      return i;
  return -1;
}

int main() {
  int array[] = {2, 4, 0, 1, 9};
  int x = 1;
  int n = sizeof(array) / sizeof(array[0]);

  int result = search(array, n, x);

  (result == -1) ? cout << "Element not found" : cout << "Element found at index: " << result;
}

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LinearSearch Complexities

Time Complexity: O(n)

Space Complexity: O(1)

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LinearSearch Applications

1. For searching operations in smaller arrays (<100 items).

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Sorting and Searching Algorithms