Help with An Array Of Objects

[David Barry]

I have an array of objects. I am wondering how to print out the values of the array. Below you will see my code. I need some help with this, please.

 
//initialization of array of objects
        Fillup[] fillup = {new Fillup(1, 1, 154630, 154883, 253, 19.384, 1.839, 35.65, 13.05, 0.076),
                             new Fillup(2, 7, 154883, 155125, 242, 19.28, 1.959, 37.78, 12.55, 0.079),
                               new Fillup(3, 14, 155125, 155368, 243, 18.764, 1.929, 36.20, 12.95, 0.077)};

        System.out.printf("%1s\n",fillup[0]);
   

[Ryan Beckett]

  import java.io.*;
import java.text.DateFormat;
import java.util.*;

public class Fillup
{	
	double[] b;
	Fillup(double... b)
	{
		this.b = new double[b.length];
		for(int i = 0; i < this.b.length; i++)
		{
			this.b[i] = b[i];
		}
	}
	public String toString()
	{
		StringBuffer s = new StringBuffer();
		for(double i: b)
			s.append(i+" ");
		return s.toString();
	}
	public static void main(String[] args) throws Exception 
	{
		 Fillup[] fillup = {new Fillup(1, 1, 154630, 154883, 253, 19.384, 1.839, 35.65, 13.05, 0.076),  
				            new Fillup(2, 7, 154883, 155125, 242, 19.28, 1.959, 37.78, 12.55, 0.079),  
				            new Fillup(3, 14, 155125, 155368, 243, 18.764, 1.929, 36.20, 12.95, 0.077)};  
				   
		for(Fillup f: fillup)
			System.out.println(f);
	}	
}  

[David Barry]

What do you mean by toString()?

[Campbell Ritchie]

David Barry wrote:What do you mean by toString()?

Look at this, and this.

[David Barry]

Ok. I think I understand what this is supposed to. I am just not getting how to correctly implement in my code. I have tried several things. Am I close with this?

  
System.out.printf("%1s\n",fillup[0].toString());
  

[Campbell Ritchie]

Yes that should work, but a few minor enhancements . . .

Miss out the 1. That would suggest you want your print-out to be 1 character wide.

If you are using printf, it is probably better to use %n which produces a system-dependent output, than \n.

In the code you quoted, you can leave out the toString() bit. You just write fillup[0] and it calls toString automatically.

You will of course have to write something in the fillup toString() method.

[Hunter McMillen]

Well actually that would print out the same thing.

Example:

public class Student
{
    String name;
    char sex;
    
    public Student(String n, char s)
   {
       this.name = n;
       this.sex = s;
   }

   public String toString()
   {
       return "Name: " + this.name + "\tGender: " + this.sex;
   } 

    public static void main(String[] args)
   {
      Student x = new Student("Sydney", 'F');

      System.out.println(x);

      System.out.println(x.toString());
   }
}

output:
Name: Sydney Gender: F
Name: Sydney Gender: F

[David Barry]

Thanks for the advice/help. I figured I would print it like this:

System.out.println("Fill Up       Days       Start Miles       End Miles       Distance       Gallons Used       Price       Cost       MPG");
        System.out.printf("%1d%16d%16d%17d%14d%20.3f%15.3f%11.2f%10.2f%n",fillup[0].getFill1(),fillup[0].getDay1(), fillup[0].getSMiles(),fillup[0].getEMiles(),fillup[0].getDistance1(),fillup[0].getGallonsUsed(),fillup[0].getPricePGal(),fillup[0].getTotalCost(),fillup[0].getMPG1());
        System.out.printf("%1d%16d%16d%17d%14d%20.3f%15.3f%11.2f%10.2f%n",fillup[1].getFill1(),fillup[1].getDay1(), fillup[1].getSMiles(),fillup[1].getEMiles(),fillup[1].getDistance1(),fillup[1].getGallonsUsed(),fillup[1].getPricePGal(),fillup[1].getTotalCost(),fillup[1].getMPG1());
        System.out.printf("%1d%16d%16d%17d%14d%20.3f%15.3f%11.2f%10.2f%n",fillup[2].getFill1(),fillup[2].getDay1(), fillup[2].getSMiles(),fillup[2].getEMiles(),fillup[2].getDistance1(),fillup[2].getGallonsUsed(),fillup[2].getPricePGal(),fillup[2].getTotalCost(),fillup[2].getMPG1());
        System.out.println();
        System.out.printf("Totals:%57d%20.3f%26.2f\n",totalDistance1,totalGallons1,totalCost1 );
        System.out.printf("Annual Projections:%45d%20.3f%26.2f%10.2f%n",ProjecDist1,ProjecGal1,ProjecCost1,ProjecMpg1);