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javaprintf
D. Spigle
D. Spigle

Reputation: 551

Double % formatting question for printf in Java

%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\n", bal, nm);

..an exception is thrown telling me that %d != lang.double. Ideas?

Upvotes: 33

Views: 188144

Answers (4)

Salazar
Salazar

Reputation: 91

Following is the list of conversion characters that you may use in the printf:

%d – for signed decimal integer

%f – for the floating point

%o – octal number

%c – for a character

%s – a string

%i – use for integer base 10

%u – for unsigned decimal number

%x – hexadecimal number

%% – for writing % (percentage)

%n – for new line = \n

Upvotes: 9

Andy
Andy

Reputation: 2507

Yes, %d is for decimal (integer), double expect %f. But simply using %f will default to up to precision 6. To print all of the precision digits for a double, you can pass it via string as:

System.out.printf("%s \r\n",String.valueOf(d));

or

System.out.printf("%s \r\n",Double.toString(d));

This is what println do by default:

System.out.println(d)

(and terminates the line)

Upvotes: 3

Adeel Ansari
Adeel Ansari

Reputation: 39907

Yes, %d means decimal, but it means decimal number system, not decimal point.

Further, as a complement to the former post, you can also control the number of decimal points to show. Try this,

System.out.printf("%.2f %.1f",d,f); // prints 1.20 1.2

For more please refer to the API docs.

Upvotes: 31

codaddict
codaddict

Reputation: 455282

%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

Upvotes: 75

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