Align Double (Variable) Columns in System Output

Question

import javax.swing.JOptionPane;
public class HW {
public static void main(String[] args)
{
    String x1 = JOptionPane.showInputDialog(null, "X: ");
    String y1 = JOptionPane.showInputDialog(null, "Y: ");
    double x = Double.parseDouble(x1);
    double y = Double.parseDouble(y1);
    System.out.println("Sum: " + (x+y));
    System.out.println("Difference: " + (x-y));
    System.out.println("Product: " + (x*y));
    System.out.println("Average: " + (x+y)/2);
    System.out.println("Distance: " + Math.abs(x-y));
    System.out.println("Maximum Value: " + Math.max(x,y));
    System.out.println("Minimum Value: " + Math.min(x,y));
    }
}

Basically, I'm trying to output the values to be like:

Sum:        5
Difference: 10
Product:    7
etc.

I've found how to do this with strings, but I'm unsure how to accomplish this with variables.

Calculate the maximum length of all strings. It will be easier if they are in array. And then PAD when printing. Look at [this SO post](http://stackoverflow.com/questions/388461/how-can-i-pad-a-string-in-java) for ideas how to PAD in Java. — PM 77-1, Sep 30 '13 at 20:55

score 1 · Accepted Answer · answered Sep 30 '13 at 20:49

Simplest solution, hardcode the number of tabs necessary to line up the text. Fine for small programs like this.

public static void main(String[] args)
{
    String x1 = JOptionPane.showInputDialog(null, "X: ");
    String y1 = JOptionPane.showInputDialog(null, "Y: ");
    double x = Double.parseDouble(x1);
    double y = Double.parseDouble(y1);
    System.out.println("Sum: \t\t" + (x+y));
    System.out.println("Difference: \t" + (x-y));
    System.out.println("Product: \t" + (x*y));
    System.out.println("Average: \t" + (x+y)/2);
    System.out.println("Distance: \t" + Math.abs(x-y));
    System.out.println("Maximum Value: \t" + Math.max(x,y));
    System.out.println("Minimum Value: \t" + Math.min(x,y));
}

You may have to add additional '\t' (tab) characters to make it line up. The reason I left a space before the '\t' is so that you guarantee there will be at least 1 whitespace between label and value. (Tab can have no effect if cursor is at a certain position already)

This seemed the easiest and most efficient way to do it. Thanks. — Modify You, Sep 30 '13 at 23:32

score 0 · Answer 2 · answered Sep 30 '13 at 20:56

I would use StringBuffer instead to calculate prefix length:

public  class HelloWorld  {

 public static void main(String args[]){

 String x = JOptionPane.showInputDialog(null, "X: ");
 String y = JOptionPane.showInputDialog(null, "Y: ");       


System.out.println(print("Sum:", (x+y)+""));
System.out.println(print("Difference:", (x-y)+""));
System.out.println(print("Product:", (x*y)+""));
System.out.println(print("Average:", (x+y)/2+""));
System.out.println(print("Distance:", Math.abs(x-y)+""));
System.out.println(print("Maximum Value:", Math.max(x,y)+""));
System.out.println(print("Minimum Value:", Math.min(x,y)+""));
}   

private static String print(String prefix, String value){
    StringBuilder buff = new StringBuilder();

    int length = prefix.length();

    int mLength = 15; // this is your gap between title and value

    buff.append(prefix);

    while(length <= mLength){
        buff.append(" ");
        length++;
    }

    buff.append(value);

    return buff.toString();
}

 }

Output:

Sum:            7.0
Difference:     -3.0
Product:        10.0
Average:        3.5
Distance:       3.0
Maximum Value:  5.0
Minimum Value:  2.0

Align Double (Variable) Columns in System Output

2 Answers2