docs: add documentation for linear search

Added documentation and clarifying comments to the linear search example
(no functional/algorithmic changes)

Author: Guddu-06

searching/linear_search.c

@@ -1,11 +1,34 @@
+/* Linear Search Algorithm
+ *
+ * This program demonstrates the linear search technique, where each element
+ * of the array is checked sequentially until the target value is found.
+ *
+ * Time Complexity:
+ *  - Best case: O(1)
+ *  - Worst case: O(n)
+ *
+ * Space Complexity:
+ *  - O(1)
+ *
+ * Works on both sorted and unsorted arrays.
+ */
 #include <stdio.h>
 #include <stdlib.h>
-
+/*
+ * Performs linear search on an integer array.
+ *
+ * @param arr   Pointer to the array
+ * @param size  Number of elements in the array
+ * @param val   Value to search for
+ *
+ * @return 1 if the value is found, otherwise 0
+ */
 int linearsearch(int *arr, int size, int val)
 {
     int i;
     for (i = 0; i < size; i++)
     {
+        // Compare each element with the target value
         if (arr[i] == val)
             return 1;
     }
@@ -22,7 +45,7 @@ int main()
     printf("Enter the contents for an array of size %d:\n", n);
     for (i = 0; i < n; i++)
         scanf("%d", &a[i]);  // accepts the values of array elements until the
-                             // loop terminates//
+                             // loop terminates
 
     printf("Enter the value to be searched:\n");
     scanf("%d", &v);  // Taking input the value to be searched