如何使用来自不同方法的变量

Question

This is a grocery store problem that asks the user for what they are buying, how much of it and the price. The final price would then be calculated for each item (I have yet to do that for item 2 and 3)

I want to know how to use quantity1 and price1 from my getInfo() method into my calc() method.

The error code I get is:

   assignment_2.java:62: error: cannot find symbol
          double total1 = quantity1 * price1;
                          ^
      symbol:   variable quantity1
      location: class assignment_2
    assignment_2.java:62: error: cannot find symbol
          double total1 = quantity1 * price1;
                                      ^
      symbol:   variable price1
      location: class assignment_2

My code:

import java.util.Scanner;
public class assignment_2
{
   public static void main(String[] args)
   {
      // Call methods here
      getInfo();
      calc();
   }

   public static void getInfo()
   {
      Scanner input = new Scanner(System.in);

      > Here I'm asking the user for the name of item 1
      // Item 1
      System.out.println("Name of item 1: ");
      String item1 = input.nextLine();

      > Here I'm asking the user for the quantity of item 1
      System.out.println("Quantity of item 1: ");
      int quantity1 = input.nextInt();

      > Here I'm asking the user for the price of item 1
      System.out.println("Price of item 1: ");
      double price1 = input.nextDouble();

      // Item 2
      Scanner input2 = new Scanner(System.in);

      System.out.println("Name of item 2: ");
      String item2 = input2.nextLine();

      System.out.println("Quantity of item 2: ");
      int quantity2 = input2.nextInt();

      System.out.println("Price of item 2: ");
      double price2 = input2.nextDouble();

      // Item 3
      Scanner input3 = new Scanner(System.in);


      System.out.println("Name of item 3: ");
      String item3 = input3.nextLine();

      System.out.println("Quantity of item 3: ");
      int quantity3 = input3.nextInt();

      System.out.println("Price of item 3: ");
      double price3 = input3.nextDouble();

      // Calculations
      // double total1 = quantity1 * price1;
      // System.out.println("Item 1 total: " + total1);

      // double total2 = quantity2 * price2;
      // System.out.println("Item 2 total: " + total2);

      // double total3 = quantity3 * price3;
      // System.out.println("Item 3 total: " + total3);     
   }
   public static void calc()
   {
      double total1 = quantity1 * price1;
      System.out.println("Item 1 total: " + total1);
   }
}

Answer 1

Pass the param into your method

public static void getInfo() {
      // Item 3
      Scanner input3 = new Scanner(System.in);
      System.out.println("Name of item 3: ");
      String item3 = input3.nextLine();

      System.out.println("Quantity of item 3: ");
      int quantity3 = input3.nextInt();

      System.out.println("Price of item 3: ");
      double price3 = input3.nextDouble();
      double total = calc(quantity, price3);
}
public static double calc(int quantity, double price)
   {
      double total = quantity * price;
      System.out.println("Item 1 total: " + total1);
      return total
   }

Answer 2

Your variables that in getInfo() method are available just from that method. You could pass variables as parameters to calc(int quantiy, double price) or define your variables as class visible(global) variables. I strictly recomend to you check; scope of variables in java .