Java error: Non Static reference

youcancallmeal

So I was reading my Deitel&Deitel Java book and decided to try out one of the examples/ Its for printing out the values of Fibonacci numbers.

public class FibonacciCalculator
{
   
  public long fibonacci( long number )
  {
    if ( ( number == 0 ) || ( number == 1 ) )
      return number;
    else
      return fibonacci( number - 1 ) + fibonacci( number - 2);
  }

  public void displayFibonacci( )
  {
    for ( int counter =0; counter <= 10; counter++ )
      System.out.printf( "Fibonacci of %d is: %d\n" , counter, 
      fibonacci( counter ) );
  }
 
}

public class FibonacciTest
{
  
  public static void main( String[] Args )
  {

    FibonacciCalculator fibonacciCalculator = new FibonacciCalculator();
    FibonacciCalculator.displayFibonacci( );
  }
}

The problem is that the line "FibonacciCalculator.displayFibonacci( );" in the main method won't work because the method "display.Fibonacci" is not static. The error message is returned is:

non-static method displayFibonacci() cannot be referenced from a static context

Acccording to the book the output should be as follows

Fibonacci of 0 is: 0
Fibonacci of 1 is: 1
Fibonacci of 2 is: 1
Fibonacci of 3 is: 2
Fibonacci of 4 is: 3
.....
Fibonacci of 10 is: 55

Is there any way to change the method displayFibonacci to be a variable?

fasty

It should be

fibonacciCalculator.displayFibonacci( );

not

FibonacciCalculator.displayFibonacci( );

Java is case sensitive and that's not the clearest example if you're typing it out yourself.

public class FibonacciTest
{
  
  public static void main( String[] Args )
  {

    FibonacciCalculator fibbCalc = new FibonacciCalculator();
    fibbCalc.displayFibonacci( );
  }
}

youcancallmeal

Sorry I'm an idiot should of seen that after trying to figure it out for half an hour
It wasnt my own coding its taken from the book so you could say their examples are not the clearest?
Anyway cheers!

marco_polo

youcancallme>al wrote: »

Sorry I'm an idiot should of seen that after trying to figure it out for half an hour
It wasnt my own coding its taken from the book so you could say their examples are not the clearest?
Anyway cheers!

Its just an ok book really, not terrible by any means, and it was my first java book so I have a soft spot for it. But in general I found that many of the examples are often way too complicated when they are just trying to illustrate a relatively a simple concept.

Thomas_S_Hunterson

Just don't try it for any anything above about the 45th term, as it's horrendously inefficient and will take ages to complete.

I presume it's as a demonstration of recursion yes?

youcancallmeal

Sean_K wrote: »

Just don't try it for any anything above about the 45th term, as it's horrendously inefficient and will take ages to complete.

I presume it's as a demonstration of recursion yes?

Yep. I'm writing a 2500 word essay on recursion. Its possibly the worst essay I've ever had to write and I had to handwrite a 1000 word essay on traffic cones(long story)

marco_polo

youcancallme>al wrote: »

Yep. I'm writing a 2500 word essay on recursion. Its possibly the worst essay I've ever had to write and I had to handwrite a 1000 word essay on traffic cones(long story)

Wierd topic however fear not. As I will demonstrate, 2500 words is no problem:

""method A() calls method A() which calls method A() which calls method A() ................... And they all lived happily ever after"
Best of luck