How to add 2 decimal places having 0s to an array

I want to print precision of 2 for all elements in my array.

For example, if I input 11.00, I expect output:

[11.00, 11.04, 11.09, 11.15, 11.19, 11.22]

but I get:

[11.0, 11.04, 11.09, 11.15, 11.19, 11.22]

Where the first element is missing trailing zero.

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

import static java.lang.Math.*;
public class Main{
  public static void main (String[] args){
	Scanner s = new Scanner(System.in);
	DecimalFormat df = new DecimalFormat(".00");
    df.setMaximumFractionDigits(2);
	float a=s.nextFloat();
	float arr[]= new float[6];
	// arr[0]=Float.valueOf((df.format(a+0.001)));
	arr[0]=a;
	arr[1]=a+(float)(0.04);
	arr[2]=a+(float)(0.09);
	arr[3]=a+(float)(0.15);
	arr[4]=a+(float)(0.19);
	arr[5]=a+(float)(0.22);
	System.out.println(Arrays.toString(arr));
	
  }
}

The object type in your array is a float. You cannot tell it to be a float with N decimal places, it is just a primitive value.

Typically you want to format the primitive when you need to use it, e.g. as a String.

In this case:

for( float f : arr )
{
	System.out.println( df.format( f ) );
}

Let's start with why doesn't it work? From Arrays.toString docs:

> Elements are converted to strings as by <tt>String.valueOf(float)</tt>.

The implementation of String.valueOf(float) is:

public static String valueOf(float f) {
    return Float.toString(f);
}

Therefore the df declared in your code snippet is never used.

What can you do? As @Koenigsberg mentioned in his answer, you can iterate over the array, and then add brackets on the sides, and commas between the elements.

If you can use double instead of floats, you can use java streams. Code sample will be:

System.out.println("[" + Arrays.stream(arr).mapToObj(df::format).collect(Collectors.joining(", ")) + "]");

If you can't use doubles, you can just iterate over the indices of arr:

System.out.println("[" + IntStream.range(0, arr.length).mapToObj(i -> df.format(arr[i])).collect(Collectors.joining( ", ")) + "]");