Java - always keep two decimal places even in zeroes

java decimalformat
user3044874 picture user3044874 · Dec 9, 2013 · Viewed 15.7k times · Source

I am trying to keep two decimal places, even if then numbers are zeroes, using DecimalFormatter:

DecimalFormat df = new DecimalFormat("#.00");

m_interest   = Double.valueOf(df.format(m_principal * m_interestRate));
m_newBalance = Double.valueOf(df.format(m_principal + m_interest - m_payment));
m_principal  = Double.valueOf(df.format(m_newBalance));

However for some values this gives two decimal places, and for others it doesnt. How can i fix this?

Answer

Michael Yaworski picture Michael Yaworski · Dec 9, 2013

It is because you are using Double.valueOf on the DecimalFormat and it is converting the formatted number back to a double, therefore eliminating the trailing 0s.

To fix this, only use the DecimalFormat when you are displaying the value.

If you need m_interest calculations, keep it as a regular double.

Then when displaying, use:

System.out.print(df.format(m_interest));

Example:

DecimalFormat df = new DecimalFormat("#.00");
double m_interest = 1000;
System.out.print(df.format(m_interest)); // prints 1000.00

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