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

%d is used for decimal numbers.

Format Code Meaning
Simple %dA simple decimal number
Right aligned %5dPrint right aligned in 5 characters. Fill any unused characters with spaces.
Leading zeroes %05dPrint right aligned in 5 characters. Fill any unused characters with zero.
Hexadecimal %xPrint as a hexadecimal (base 16) number.
With commas %,dUse , to separate thousands.

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

%d is used for decimal numbers.

Format Code Meaning
Simple %dA simple decimal number
Right aligned %5dPrint right aligned in 5 characters. Fill any unused characters with spaces.
Leading zeroes %05dPrint right aligned in 5 characters. Fill any unused characters with zero.
Hexadecimal %xPrint as a hexadecimal (base 16) number.
With commas %,dUse , to separate thousands.

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

Format Code Meaning
Simple {0} Simple conversion to string
Right aligned {0,12} Print right aligned in 12 characters. Fill any unused characters with spaces.
Leading zeroes {0:00000} Print right aligned in 5 characters. Fill any unused characters with zero.
Hexadecimal %x Print as a hexadecimal (base 16) number.
With commas {0,12:n0} Use , to separate thousands The whole string takes 12 characters, :n0 means number format with 0 decimal places.
#include #include using namespace std; int main () { cout << "The answer:" << " 42" << endl; return 0; } ]]> public class Demo{ public static void main(String argv[]) { System.out.printf("The answer:%d\n", 42); System.out.printf("The answer:%12d\n", 42); System.out.printf("The answer:%05d\n", 42); System.out.printf("The answer:%x\n", 42); System.out.printf("The answer:%,d\n", 42000000); } }