Question

1. Write a program Adder.java that calculates and prints the sum of command line parameters, so if you make the command line parameters be 2 5 22 then the program prints 29.

2. Write a program ShowFiles.java that assumes the command line parameters are each a text file name directly readable by the program. For each file named, print out the three heading lines in the format shown, and then each line of the file contents.

   If file q.txt contains

   What is the answer

   to the universe

   and everything?

   and file ans.txt contains

   The answer is

   42.

   Then calling ShowFiles with parameters:

   q.txt ans.txt

   prints:

   ---------------------

   q.txt

   ---------------------

   What is the answer

   to the universe

   and everything?

   ---------------------

   ans.txt

   ---------------------

   The answer is

   42.

   You will need Scanner method hasNextLine for your file reading while-loop.

Answer 1

Answer :

public class Adder {
public static void main(String[] args) {
   int sum=0;
   //iterating through the string array
   for(String str:args){
       //converting it into int and adding to sum
       sum=sum+Integer.parseInt(str);
   }
   System.out.println("Sum is : "+sum);
}
}

Answer 2:

import java.io.File;
import java.util.Scanner;

public class ShowFiles {
   public static void main(String[] args) {
       //iterating through file names
       for (String str : args) {
           showContent(str);
       }
   }

   private static void showContent(String aStr) {
       //printing header
       System.out.println("What is the answer\nto the universe\nand everything?");
       System.out.println("------------------\n"+aStr+"\n------------------");
       try {
           //opening file
           Scanner sc = new Scanner(new File(aStr));
           //iterating through reach line
           while (sc.hasNextLine()) {
               System.out.println(sc.nextLine());
           }
       } catch (Exception e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

   }
}