Question

static int find(int x, List<Integer> a) Given an integer x which is assumed to be in the list a, write a method that returns the position of the first occurrence of u in a. Positions are counted as 0, 1, 2, .... If x does not appear in the list, you should throw an IllegalArgumentException. Examples: x: 3 x: 2 a: [7, 5, 3, 8] a: [7, 5, 3, 8] ==> 2 ==> IllegalArgumentException

Given an integer x which is assumed to be in the list a, write a method that returns the position of the first occurrence of x in a. Positions are counted as 0,1,2,.... If x does not appear in the list, you should throw an IllegalArgumentException.

Answer 1

code screenshot :

import java.util.*; public class Solution{ static int find(int x,List<Integer> a) { int pos = a.indexOf(x)in indexof method return position of x in a, if it does not exist in a then returns -1 if( pos != -1){ // checking for position return pos; }else{ throw new IllegalArgumentException ("x does not exist in a "); // throwing exception with a message public static void main(String[args) { List<Integer> a=new ArrayList<Integer>(); // a.add(7); a.add(5); a.add(3); a.add(8); try{ System.out.println(find (3, a)); catch (Exception e) { System.out.println(e); try{ System.out.println(find (2, a)); catch (Exception e) { System.out.println(e);

output :

10CEBOOR. CROPI P9 C COLO CONJUU JULULLON. JUVU java.lang. IllegalArgumentException: x does not exist in a

code to copy :

import java.util.*;
public class Solution{
   static int find(int x,List<Integer> a){
       int pos = a.indexOf(x); // indexOf method return position of x in a, if it does not exist in a then returns -1
       if( pos != -1 ){ // checking for position

           return pos;

       }else{

       throw new IllegalArgumentException("x does not exist in a "); // throwing exception with a message

       }
   }
  
   public static void main(String[] args) {
       List<Integer> a=new ArrayList<Integer>(); //
      
       a.add(7);
       a.add(5);
       a.add(3);
       a.add(8);
       try{
          
           System.out.println(find(3,a));

       }
       catch (Exception e) {

           System.out.println(e);

       }

       try{
          
           System.out.println(find(2,a));

       }
       catch (Exception e) {

           System.out.println(e);

       }
      
      
   }
}

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