java as a beginnerSolutionimport statements import javaio im

java as a beginner

Solution

//import statements
import java.io.*;
import java.util.Scanner;
import java.util.ArrayList;

public class Calculation{

     //main method
     public static void main(String[] args) {
          //try so that we can catch file input exception
          try{
               //taking input from file called numbers.txt
               Scanner scanner = new Scanner(new File(\"numbers.txt\"));

               //declaring numbers arraylist and not array since we don\'t know the number of integers present in the file
               ArrayList<Integer> numbers = new ArrayList<Integer>();

               //reading integers from file and adding it to numbers arraylist
               while(scanner.hasNextInt()){
                    numbers.add(scanner.nextInt());
               }

               //initialising sum
               int sum = 0;

               //iterating through the list and adding the number
               for (int i=0; i<numbers.size(); i++){
                    //instead of if else we can add the number multiplied by -1^it\'s position in the sequence
                    sum += Math.pow(-1, i)*numbers.get(i);
               }

               //printing out the statement
               System.out.println(\"The sum of sequence is \"+sum);

          }catch(Exception e){ //catching input exception
               System.out.println(e);
          }
     }

}