Question

Just that method --> Java code

Write a method “int sumPos(List aList)” to calculate the sum of positive integers in an ADT List aList of integers using ADT List operations.

ADT List operations: isEmpty(), size(), add(index, item), remove(index), get(index), and removeAll().

You should not assume how an ADT List is implemented.

Using array indexing, head/tail references, or any operation not defined in ADT List is not allowed.

Answer 1

The required method is given below:

//method to calculate the sum of positive integers
public static int sumPos(List aList)
{
//variable declarationa and initialization
int sum=0;
  
//check if the size of the list is zero
if(aList.size()==0)
return 0;
  
//calcuate the sum of the positive number
while(!aList.isEmpty())
{
if((int)aList.get(0)>0)
{
sum = sum + (int)aList.get(0);
}
aList.remove(0);
}
  
//return the sum
return sum;
}

The complete program source code including the above method for testing is given below:

import java.util.ArrayList;
import java.util.List;

public class Main
{
//method to calculate the sum of positive integers
public static int sumPos(List aList)
{
//variable declarationa and initialization
int sum=0;
  
//check if the size of the list is zero
if(aList.size()==0)
return 0;
  
//calcuate the sum of the positive number
while(!aList.isEmpty())
{
if((int)aList.get(0)>0)
{
sum = sum + (int)aList.get(0);
}
aList.remove(0);
}
  
//return the sum
return sum;
}
  
   public static void main(String[] args)
   {
   //list declaration
   List<Integer> aList = new ArrayList<Integer>();

//add number to the list
   aList.add(0, 5);
   aList.add(1, 3);
   aList.add(2, -3);
     
   //method calling and display the result
   System.out.println(sumPos(aList));
   }
}

OUTPUT:

8