how to increase the number of decimal digits in JAVA program output?

[Dennis Racket]

I am writing a small code in java about finding a square root of a number! I should have the facility to decide how many decimal numbers will be shown after decimal points! Is there any method by which I can select how many position to show in the answer? I have declared all the variables as double but still it is showing answer up to 15 digits only! I want another method by which I can show “n” number of digits after the decimal point! Thanks!

[Shreevats]

If you want more than 15 positions then you should opt for string format or use string.format to convert double into string !
E.g: String s = String.format(“%1.20f”,1/3);
This will convert the value in to the string value! But I don’t think You will get what that you want because computer will not be able to save the value that will be coming!

[Ronchi]

I have got the program that shows how to get the value for the “PI” beyond 15 digits! You can re-edit it for your own purpose! This is working properly on my machine! Hope you will like this!

import java.math.BigDecimal;
import java.util.Scanner;
public class Pi {
public static void main(String args[])
{
Scanner input = new Scanner(System.in);
BigDecimal var1 = new BigDecimal("4");
BigDecimal var2 = new BigDecimal("4");
BigDecimal pi = new BigDecimal("0");
double var3 = 0;
System.out.print("Please enter the number of calculations the program should perform: ");
var3 = input.nextDouble();
for(double i=1;i<=var3;i+=2)
{
var1 = var2.subtract(new BigDecimal((4/(2*i+1))));
System.out.println(var1)
var2 = var1.add(new BigDecimal((4/(2*i+3))));;
System.out.println(var2);
}
pi = var1.add(var2);
pi = pi.divide(new BigDecimal("2"));
System.out.println("Pi aprox. = " + pi);
}
}