Why is my code of Linear search using "for-each loop" not working for mixed inputs?

Question

My code is working for ascending or descending array inputs like 11,12,13,14,15 etc....but it is not working for mixed order array inputs like 11 13 12 15 14.

import java.util.Scanner;
public class LinearSearch {
    public static void main(String[] args) {
        int LS[]=new int[100];                      //LS is the array
        int n,key,flag=0;                          //n is the number of array elements and key is the element to be searched
        Scanner sc=new Scanner(System.in);
        System.out.println("Enter no.of array elements");
        n=sc.nextInt();
        System.out.println("Enter array elements");
        for(int i=0;i<n;i++)
        LS[i]=sc.nextInt();
        System.out.println("Enter element to search");
        key=sc.nextInt();           
        for (int i:LS){
          if(LS[i]==key){
            flag=1;
            System.out.println(key+" is found at location "+(i+1));
          }
      }
      if(flag==0){
        System.out.println(key+" is not found");
    }  
  }
}

Answer 1

I think the problem is here: if(LS[i]==key) you need to change as if(i==key) because according to for loop for (int i:LS) i stands for elements of the array not the index.

If you want to get the index of the element, you can use a for loop instead of a foreach loop:

for(int i = 0; i<LS.length; i++) {
    if(LS[i]==key){
        flag=1;
        System.out.println(key+" is found at location "+(i+1));
      }
}

One more thing:

You're asking for the number of elements, so it would be a better practice to initialize the array with n instead of 100 :

int LS[] = new int[n]; 

When you initialize the array, it allocates the memory according to the size. Think of n equals to 20, then it would be a waste to initialize the array with size 100

Otherwise if the user enters a value greater than 100, the program throws ArrayIndexOutOfBoundsException.