Question

Write a full program that will accept exactly  three command line arguments that can be interpreted as integers, and will add them up. If there aren't exactly 3 command line arguments, print an error message and terminate the program.

Suppose your program is called Add.java.

Then running the command java Add 1 2 3 will output 6, and running java Add, for example, will cause the program to shut down.

Consider the following recursive method:

public static int mystery (int n) {

   if (n ==0)

   return 1;

   else

return 2 * mystery(n-1);

}

What is returned by a call to mystery(7)?

What is computed by the mystery method?

Answer 1

1) Program Screenshot:

Sample Output:

Program Code:

// Create a class Add
public class Add {
   // Main function
   public static void main(String[] args) {
       // Check the if there aren't exactly 3 command line arguments
       if(args.length != 3) {
           // If the length is not exactly 3 print error message and terminate the program
           System.out.println("Enter exactly 3 command line aruguments");
           return;
       }
       int sum = 0;
       // Find sum of the arguments
       for(int i = 0 ; i < args.length ; i++) {
           sum = sum + Integer.parseInt(args[i]);
       }
       // Print the sum of the arguments
       System.out.println("Sum is " + sum);

   }

}