Calling a local variable from a static function

lepel

Calling local variable from inside a static method:

Following code has this problem :

Code:

class Boat {
    int calcDir() {
        int direction = 2;
        return direction;
    }
}

public class Control {
    public static void main(String args[]){

        Boat boat = new Boat();
        boat.calcDir();
        System.out.println(direction);
    }
} 

I always get the same error:
cannot find symbol
Symbol : variable direction
Location : class Control

In this case you are calling local variable of a method calcDir() inside another class from a static method. The scope the of int direction , is the function calcDir() only.

Code:

class Boat {
   int direction;
   int calcDir() {
      return direction + 1;
   }
}

public class Control {
   public static void main(String args[]){
      int direction = 2;
      Boat boat = new Boat();
      System.out.println(boat.calcDir());
   }
} 
 

DrRakha

the int direction inside the calcDir() method , has a value of 0 . ( which is the default value of int ) . so the 0 + 1 = 0 ;

the int direction inside the main method , it's scope is bounded to the main method only . Not seen inside the class Boat .

lepel

So how do I store the calculated value in calcDir() to be able to use it in class Control?

Xyle

Since you working with 2 classes here you need to set a variables value with the calcDir() method

The first way...

Code:

class Boat {
   int calcDir() {
      int direction = 2;
      return direction;
   }
}

public class Control {
   public static void main(String args[]){
      //Declare a variable to hold the return value of calcDir()
      int tempDir = 0;
      Boat boat = new Boat();
    
      //Use the calcDir() method to fill the value of tempDir
      tempDir = boat.calcDir();

      //Print the value
      System.out.println(tempDir);
   }
}

The second way is to pass in a variable amount as a parameter to the calcDir() method...

Code:

class Boat {
   int calcDir(int tVal) {
      //Pass in a value as a parameter to the calcDir() method
      //This Value will get incremented by 1
      return tVal + 1;
   }
}

public class Control {
   public static void main(String args[]){
      int direction = 2;
      Boat boat = new Boat();
      System.out.println(boat.calcDir(direction));
   }
}

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Calling a local variable from a static function

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