Linear Search in Java

Linear search is used to search a key element from multiple elements. Linear search is less used today because it is slower than binary search and hashing.

Algorithm:

Step 1: Traverse the array
Step 2: Match the key element with array element
Step 3: If key element is found, return the index position of the array element
Step 4: If key element is not found, return -1

Let's see an example of linear search in java where we are going to search an element sequentially from an array.

public class LinearSearchExample{  
public static int linearSearch(int[] arr, int key){  
        for(int i=0;i<arr.length;i++){  
            if(arr[i] == key){  
                return i;  
            }  
        }  
        return -1;  
    }  
    public static void main(String a[]){  
        int[] a1= {10,20,30,50,70,90};  
        int key = 50;  
        System.out.println(key+" is found at index: "+linearSearch(a1, key));  
    }  
}  

Test it Now

Output:

50 is found at index: 3

Linear Search in Java (Another way)

You can also use a method where array is not predefined. Here, user has to put the elements as input and select one element to check its location.

import java.util.Scanner;
 
class LinearSearchExample2 
{
  public static void main(String args[])
  {
    int c, n, search, array[];
 
    Scanner in = new Scanner(System.in);
    System.out.println("Enter number of elements");
    n = in.nextInt(); 
    array = new int[n];
 
    System.out.println("Enter those " + n + " elements");
 
    for (c = 0; c < n; c++)
      array[c] = in.nextInt();
 
    System.out.println("Enter value to find");
    search = in.nextInt();
 
    for (c = 0; c < n; c++)
    {
      if (array[c] == search)     /* Searching element is present */
      {
         System.out.println(search + " is present at location " + (c + 1) + ".");
          break;
      }
   }
   if (c == n)  /* Element to search isn't present */
      System.out.println(search + " isn't present in array.");
  }
}

Output:

Use image LinearSearchExample

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