title: Defining Variables for use in multiple methods
body: <p>I've been at my wits end with this problem. In a class right now and for this assignment I'm needed to use the Scanner to input data and use this same data within my nested methods to calculate two things; Temperature Conversion and Currency Conversion.</p>
  
  <p>Problem I'm having is I have no idea how to define my variables throughout my whole piece of code, as I get compiler errors saying that certain variables aren't defined; e.g. <code>tC</code>, and <code>euro</code>.</p>
  
  <p>How do I assign those two variables to be able to compile this correctly?</p>
  
  <pre><code>import java.util.Scanner;
  
  public class MethodsMS {
  
      // required main method of the class
      public static void main(String [] args) {
  
          performTemperatureConversion();
          System.out.println();  // blank line
          performCurrencyConversion();
  
          double numDouble;
  
  
      } // end main
  
      // (no changes needed above this point)
      //--------------------------------------------------------------
      // (write the following methods)
  
      //--------------------------------------------------------------
  
      // write method to perform temperature conversion...
      public static void performTemperatureConversion() 
      {
          double numDouble;
          readDouble();
          degreeConversion();
          display();
  
      }
  
      //--------------------------------------------------------------
  
      // write method to perform currency conversion...
      public static void performCurrencyConversion() 
      {
          readDouble();
          currencyConversion();
          display();
  
      }
  
      //--------------------------------------------------------------
  
      // write method to obtain an input double value (use Scanner)...
      public static double readDouble()
      {
          double numDouble;
          Scanner input = new Scanner(System.in); 
          System.out.print("Enter a double number: ");
          numDouble = input.nextDouble();
  
          return numDouble;
  
      }
  
      //--------------------------------------------------------------
  
      // write method to print an input string inside a formatted box...
      public static void display()
      {
          System.out.print("Conversion number is now: " + numDouble);
      }
  
      //--------------------------------------------------------------
  
      // write method to convert F to C...
      public static void degreeConversion()
      {
          double numDouble, tC;
          tC = (numDouble - 32) * 5/9;
  
          return;
  
      }
      //--------------------------------------------------------------
  
      // write method to convert $ to Euros...
      public static void currencyConversion()
      {
          double euro;
          euro = numDouble * 0.894614;
  
          return euro;
      }
  } // end class
  </code></pre>