The printf method takes a format string as the first parameter. This string is printed but the parameters that follow replace the % placeholders.

%f is used for floating point values.

Format Code Meaning
Simple %fThe default format
Fixed decimal places %.3f Print three decimal places.
Right justified %8.3Print right aligned in 8 characters. Use three decimal places.

The Write method takes a format string as the first parameter. This string is printed but following parameters replace the {} placeholders.

In the phrase {0:8:f3} 0 indicates the first parameter 8 is the number of spaces to use (right justified), f3 means three decimal places.

Format Code Meaning
Simple {0} Simple conversion to string
Three dp {0:f3} Three decimal places.
Right aligned {0,8:f3} Print right aligned in 8 characters. Use three decimal places.
public class Demo{ public static void main(String[] argv) { System.out.printf("The answer:%f\n", Math.PI); System.out.printf("The answer:%.3f\n", Math.PI); System.out.printf("The answer:%8.3f\n", Math.PI); } }