Question

Function name: triangular Parameters: integer Returns: a list Description: Write a function called triangular that accepts one integer parameter that returns a list with the same number of terms as the value of the parameter. If the parameter is zero or a negative number, you should return an empty list A triangular number is the sum of a positive integer and all the integers before it. The series is as follows: 1, 3, 6, 10, 15, 21,

Answer 1

please fidn the code 1

import java.util.ArrayList;
import java.util.Scanner;

public class Triangular {
   public static void main(String args[]){
       Scanner sc = new Scanner(System.in);
       System.out.print("Enter the size of the list: ");
       int size = sc.nextInt();
      
       ArrayList<Integer> list = triangular(size);
       System.out.println(list.toString());
   }
   public static ArrayList<Integer> triangular(int n){
       int sum=0;
       ArrayList<Integer> list1 = new ArrayList<Integer>();
       if(n<=0)
           return list1;
       else{
           for(int i=0;i<n;i++){
               sum = sum+(i+1);
               list1.add(sum);
           }
       }  
       return list1;
   }
}

2) mthod for sum list

private static int sumList(ArrayList lis1){
       int sum=0;
       for(int i=0;i<lis1.size();i++){
           sum = sum + (Integer)lis1.get(i);
       }
       return sum;
   }