DecimalFormat

import java.text.DecimalFormat;

//	http://stackoverflow.com/questions/1899138/formatting-strings-in-java
//	http://www.coderanch.com/t/417160/java/java/cut-double-decimal-point
//	http://www.javaservice.net/~java/bbs/read.cgi?m=devtip&b=javatip&c=r_p&n=931308733
//	http://www.javaservice.net/~java/bbs/read.cgi?m=devtip&b=javatip&c=r_p&n=920434490
//		유효숫자의 개수에 따라 소수점 위와 아래의 표현할 수 있는 숫자의 개수가 달라짐
//		e.g.	소수 이하의 자리수를 유효숫자 2자리까지 필요하다면
//				그 수치는 70조(70,368,744,177,663.99)까지 

public class TestDecimalFormat {
	public static void printDFNum(double d)
	{
		System.out.printf("double %%f\t%f\n", d);
		System.out.printf("double %%g\t%g\n", d);
		System.out.printf("double %%G\t%G\n", d);
		DecimalFormat[]	dfArray	=	{
			new DecimalFormat("0.#"), new DecimalFormat("0.##"),
			new DecimalFormat("0.###"), new DecimalFormat("0.####"),
			new DecimalFormat("0.#####"), new DecimalFormat("0.######"),
			new DecimalFormat("0.#######"),
			new DecimalFormat("0.##############################"),
			new DecimalFormat("0.#E0"), new DecimalFormat("0.##E0"),
			new DecimalFormat("0.###E0"), new DecimalFormat("0.####E0"),
			new DecimalFormat("0.#####E0"), new DecimalFormat("0.######E0"),
			new DecimalFormat("0.#######E0"),
			new DecimalFormat("0.##############################E0"),
		};
		for ( DecimalFormat df : dfArray )
			System.out.println(df.getMaximumFractionDigits() + "\t" + df.format(d));
	}
	public static void main(String[] args)
	{
		double[]	dArray	=	{	2480965783.760506D,
			6155191220190383100.123456D,
			6.155191220190383100123456E18
		};
		
		System.out.println("Double.MAX_VALUE\t" + Double.MAX_VALUE);
		for ( double d : dArray )	printDFNum(d);
	}
}