#4: The Console Matters

public class Homework1 {

  public static void main(String[] args) {
 
    System.out.println(
      "Please enter numbers, 1 to a line, -1 to quit");
    double sum = 0.0;
    while (true) {
      int i = System.readInt();
      if (i == -1) break;
      sum = sum + readInt();   
    } 
    System.out.println("The sum is " + sum);
  }

}

The right way:

public class Homework1 {

  public static void main(String[] args) {
 
    double sum = 0;
    for (int i = 0; i < args.length; i++) {
      sum = sum + Double.parseDouble(args[i]);   
    } 
    System.out.println("The sum is " + sum);
  }

}