使用扫描仪时遇到的阵列错误

Question

I'm working on an assignment. Parallel arrays are required... I need help with a couple of things, well, at least three things.

• The first issue when I run the program all the way through. How do I add spaces in the print statement? It comes out like this "MondaySoda1.0"
• Another problem is the "1.0" I clearly have "1.25" for price [0] but why is it printing out "1.0"?
• Lastly, if I type in Tuesday where it asks "Which day of the week do you want...." It stills prints out the information for Monday. How do I code it where if you type in Tuesday, it does not print anything at all.

I'll appreciate any help at this point!

import java.util.Scanner;
public class Cafeteria  
{
public static void main (String [] args)
{

  String [] days = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday   ", "Saturday   ", "Sunday   "};   
  String [] drinks = {"Soda", "Sweet Tea", "Lemonade", "Frozen Lemonade", "Coffee-Hot", "Coffee-Iced", "Latte"}; 
  double [] price; = {1.25, 1.50, 1.75, 2.00, 2.25, 2.50, 3.75};

  for ( int i = 0; i < days.length; i++)
  {

  }  

  Scanner scan = new Scanner(System.in);
  System.out.println("What is the price of a Soda? ");
  price [0] = scan.nextDouble();

  System.out.println("What is the price of a Sweet Tea? ");
  price [1] = scan.nextDouble();

  System.out.println("What is the price of a Lemonade? ");
  price [2] = scan.nextDouble();

  System.out.println("What is the price of a Frozen Lemonade? ");
  price [3] = scan.nextDouble();

  System.out.println("What is the price of a Coffee-Hot? ");
  price [4] = scan.nextDouble();

  System.out.println("What is the price of a Coffee-Iced? ");
  price [5] = scan.nextDouble();

  System.out.println("What is the price of a Latte? ");
  price [6] = scan.nextDouble();
  System.out.println();

  scan.nextLine();
  System.out.println("Which day of the week do you want the discounted drink price for?");
  String day = scan.nextLine();
  System.out.println();



  System.out.println("Weekday     Drink       Original-Price     Discount-Price");
  System.out.println("----------------------------------------------------------");
  System.out.println(days[0] + drinks[0] + price[0]); //Print out the list of the desire array when you enter a day in


  System.out.println("The highest price drink is latte at $3.75");


 }
}

Answer 1

Ok here we go...

• How do I add spaces in the print statement?

  Add spaces as shown below

   System.out.println(days[0] + " " + drinks[0] + " " + price[0]); 

• Another problem is the "1.0" I clearly have "1.25" for price [0] but why is it printing out "1.0"?

  Not sure what you mean, but if you input 1 it outputs 1.0 so on and so forth

• Which day of the week do you want...." It stills prints out the information for Monday. How do I code it where if you type in Tuesday

  This is happening because you are storing the input in day and trying to use the index of array days . Just print out the day variable, you dont need the array days .

    System.out.println(day + " " + drinks[0] + " " + price[0]); 

Answer 2

First of all you have an extra semicolon after the price variable that should result in a compilation error:

double [] price; = {1.25, 1.50, 1.75, 2.00, 2.25, 2.50, 3.75};

Secondly you never use the values you instantiate the array with, you assign new values as you run the program. So if you answer the first question - "What is the price of a Soda?" - with 1 , then the end result will be 1.0 .

Thirdly, to add the required space, just add it when you print out the result:

System.out.println(days[0] + "  " + drinks[0] + "  " + price[0]);

Answer 3

Parallel arrays is not a thing, but you could of course make a new class, called eg, Drink.

public class Drink {
    String drink;
    double price;

    public Drink(String drink) {
        this.drink = drink;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public String getDrink() {
        return drink;
    }

    public double getPrice() {
        return price;
    }
}

This way, you can use the constructor to create the drink and the setter to set the price, after you got the user input. You could also include a field for discount (or discount of the day) or something.

In your scenario, not sure where the days are for...