Chapter5-UsingPre-BuiltMethods.ppt

* * * * * * * * * * * * * * Format Specifier Details Heres the syntax for a format specifier: %[flags][width][.precision]conversion-character The square brackets indicate that something is optional. So the flags, width, and precision parts are optional. Only the % and the conversion character are required. 31 Conversion Character The conversion character tells the Java Virtual Machine (JVM) the type of thing that is to be printed. Here is a partial list of conversion characters: s This displays a string. d This displays a decimal integer (an int or a long). f This displays a floating-point number (a float or a double) with a decimal point and at least one digit to the left of the decimal point. e This displays a floating-point number (float or double) in scientific notation. 32 Conversion Character This code fragment illustrates how to use the conversion characters: System.out.printf(Planet: %s\n, Neptune); System.out.printf(Number of moons: %d\n, 13); System.out.printf(Orbital period (in earth years): %f\n, 164.79); System.out.printf( Average distance from the sun (in km): %e\n, 4498252900.0); Here is the output: Planet: Neptune Number of moons: 13 Orbital period (in earth years): 164.790000 Average distance from the sun (in km): 4.498253e+09 33 Precision and Width Precision: Applies only to floating-point numbers (i.e., it works only in conjunction with the f and e conversion characters). Its syntax consists of a dot and then the number of digits that are to be printed to the right of the decimal point. If the data item has more fractional digits than the precision specifiers value, then rounding occurs. If the data item has fewer fractional digits than the precision specifiers value, then zeros are added at the right so the printed value has the specified number of fractional digits. Width: Specifies the minimum number of characters that are to be printed. If the data item contains more than the specified number of characters, then