printf type specifier

Question

I now want to know that means this line:

printf("Answer: %00010.6f", 22);

He prints: 022.000000. But way? i know whar 6f means float.

thansk for answers

Answer 1

printf("Answer: %f", 22) would enter the number 22 to the string "Answer: %f" in the place of the "%f" and print it as a float ("f" is for "float"). The numbers between the "%" and the "f" are to set the format - the number of digits that the printout will have.

Answer 2

The printf() syntax and meanings are very well-documented. Look at the printf(3) man page or the Wikipedia printf entry.

The particular example you gave means: print a floating point number. Give it 6 characters after the decimal point. Then prefix it with zeros until it is at least 10 characters.

Answer 3

this format string means:

• use 0 as filling character
• fill to a minimum of 3 characters before the . ( 2 -> 002, 23 -> 023, longer numbers stay as they are)
• display exactly 10 characters (including the delimiter)
• use . as decimal delimiter
• display 6 digits after the delimiter
• type float

Answer 4

After initially thinking this was C (result of long habit), I realize this is for PHP. Mostly the same, but the constant seems to be handled differently.

Anyway, the parameters in your code break down as follows:

• f = print the number as a floating point
• 10 = total field width of ten digits
• 000 = print up to 3 leading zeros when applicable (i.e. if there aren't 3 significant figures left of the decimal point)
• . = use a dot as the decimal separator
• 6 = six places after the decimal

It seems the printing parameters for PHP's printf are actually on the sprintf page.