Linear Search Program in C

We’ll talk about the linear search algorithm in this article. Finding a certain element in the list is the process of searching. The procedure is considered effective and returns the element’s location if the element is contained in the list, if not, the search is considered failed.

Binary search and linear search are two frequently used search techniques. Therefore, we shall talk about the widely used linear search algorithm here.

Linear Search

A sequential search algorithm is another name for linear search. It is the most straightforward search algorithm. In a linear search, we just go through the list in its whole and match each element with the item whose position has to be found. The algorithm returns the item’s location if a match is made; otherwise, it returns NULL.

It is frequently used to search for a certain element in an unordered list or a list where the entries are not sorted. The linear search’s worst-case time complexity is O(n).

Steps of Linear Search

The steps used in the implementation of Linear Search are listed as follows –
First, we have to traverse the array elements using a for loop.
In each iteration of for loop, compare the search element with the current array element, and –
If the element matches, then return the index of the corresponding array element.
If the element does not match, then move to the next element.
If there is no match or the search element is not present in the given array, return -1.
Now, let’s see the algorithm of linear search.

Linear Search Algorithm:

let’s say the array is X and the value is i;

  • Set j to 1
  • If j > n, jump to step 7
  • If X[j] == i, jump to step 6
  • Then, increment j by 1 i.e. j = j+1
  • Go back to step 2
  • Display the element i which is found at particular index i, then jump to step 8
  • Display element not found in the set of input elements.
  • Exit/End

    How Linear Search Algorithm Work?

    To find an element in the list below with the value k = 1, follow these steps.

    Array to be searched for

  1. Compare each element x with k starting with the first element.

  2. Return the index if x == k.

  3. Else, return not found.

C Program Code for Linear Search

#include <stdio.h> 
int LINEAR_SEARCH(int inp_arr[], int size, int val) 
	for (int i = 0; i < size; i++) 
		if (inp_arr[i] == val) 
			return i; 
	return -1; 
int main(void) 
	int arr[] = { 10, 20, 30, 40, 50, 100, 0 }; 
	int key = 100; 
	int size = 10; 
	int res = LINEAR_SEARCH(arr, size, key); 
	if (res == -1)
	printf("ELEMENT NOT FOUND!!");
    printf("Item is present at index %d", res);    
	return 0; 

Linear Search Complexities:

Time complexity: O(N) will be the time complexity for performing linear search.

Space complexity: O(1) will be the space complexity for performing linear search.

With this, we come to the end of this blog on ‘Linear Search in C’. I hope you found it informative.

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