how to print 09 if the int variable is 9 in C?

Question

any existing function to do that in c?

Answer 1

sprintf with formatting codes like %02d will give you two decimal places.

here's an example of the command sprintf( string, "file.%d", file_number );

Here it puts the string "file.2" into the variable named string, assuming that 2 was in the variable named file_number.

you can use multiple like so: sprintf(str, "%02d/%02d/%4d",day,month,year);

Look up the specs on sprintf for other kinds of formatting like floating point significant digits.

Answer 2

printf("%02d", 9);

Answer 3

Along with "%02d" you can use "%2.2d" if you prefer. The latter style is handy when/if the actual width is in a variable so you do something like this:

int width = 2;
int value = 9;

printf("%*.*d", width, width, value);