Double % formatting question for printf in Java

Question

%s is a string in printf, and %d is a decimal I thought...yet when putting in

writer.printf(\"%d dollars is the balance of %s\\r\\         


        

Answer 1

%d is for integers use %f instead, it works for both float and double types:

double d = 1.2;
float f = 1.2f;
System.out.printf("%f %f",d,f); // prints 1.200000 1.200000