Java Program to Perform a Linear Search

Write a Java program to perform a linear search on arrays. In this example, the for loop traverses the array of items from start to end.

The if statement checks each number against the search item. If it finds the match, printing the index position and break statement helps the javac exit from the loop.

package Remaining;

import java.util.Scanner;

public class LinearSearch0 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		int i;
		
		sc = new Scanner(System.in);		
		
		int[] arr = {10, 20, 40, 60, 80, 100, 120, 150};
		
		System.out.print("Please Enter Number to Search =  ");
		int num = sc.nextInt();
		
		for(i = 0; i < arr.length; i++) 
		{
			if(arr[i] == num) 
			{
				System.out.println("The Index Position of " + num + " = " + i);
				break;
			}
		}
		if(i == arr.length)
		{
			System.out.println("Number Not Found");
		}
	}
}

This example accepts the user input array size and items and performs the linear search to find the number.

package Remaining;

import java.util.Scanner;

public class LinSea1 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		int Size, i;
		
		sc = new Scanner(System.in);		
		System.out.print("Please Enter the size = ");
		Size = sc.nextInt();
		
		int[] arr = new int[Size];
		
		System.out.format("Enter %d elements = ", Size);
		for(i = 0; i < Size; i++) {
			arr[i] = sc.nextInt();
		}
		
		System.out.print("Please Enter Number to Find =  ");
		int num = sc.nextInt();
		
		for(i = 0; i < arr.length; i++) 
		{
			if(arr[i] == num) 
			{
				System.out.println("The Index Position of " + num + " = " + i);
				break;
			}
		}
		if(i == arr.length)
		{
			System.out.println("Number Not Found");
		}
	}
}

Please Enter the size = 8
Enter 8 elements = 11 23 45 67 77 89 98 100
Please Enter Number to Find =  98
The Index Position of 98 = 6

Java Program to perform a linear search on arrays using functions

package Remaining;

import java.util.Scanner;

public class LinSea2 {
	private static Scanner sc;
	
	public static void main(String[] args) {
		
		sc = new Scanner(System.in);		
		System.out.print("Please Enter the size = ");
		int Size = sc.nextInt();
		
		int[] arr = new int[Size];
		
		System.out.format("Enter %d elements = ", Size);
		for(int i = 0; i < Size; i++) {
			arr[i] = sc.nextInt();
		}
		
		System.out.print("Please Enter Number to find =  ");
		int num = sc.nextInt();
		
		int result = lnSea(arr, num);
		if(result == -1)
		{
			System.out.println("Number Not Found");
		}
		else
		{
			System.out.println("The Index Position of " + num + " = " + result);

		}
	}
	
	public static int lnSea(int arr[], int num)
	{
		for(int i = 0; i < arr.length; i++) 
		{
			if(arr[i] == num) 
			{
				return i;
			}
		}
		return -1;
	}
}

Please Enter the size = 6
Enter 6 elements = 22 30 45 80 90 120
Please Enter Number to find =  90
The Index Position of 90 = 4