# Printf "%#6.4o\\n"

**URL:** <https://www.ruby-forum.com/t/printf-6-4o-n/127237>\
**Category:** Development\
**Created:** [January 26, 2008, 8:04pm UTC](https://www.ruby-forum.com/t/printf-6-4o-n/127237 "2008-01-26T20:04:33Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [January 26, 2008, 8:04pm UTC](https://www.ruby-forum.com/t/printf-6-4o-n/127237/1 "2008-01-26T20:04:33Z")

</div>

printf e$B$Ge(B %#6.4o e$B$K$h$je(B 1, 0, -1  
e$B$r%U%)!\<%^%C%H$7$?7k2L$O0Je(B  
e$B2\<$N$h$&$K$J$j$^$9!#e(B

% ./ruby -ve ‘1.downto(-1) {|n| printf “%#6.4o\n”, n }’  
ruby 1.9.0 (2008-01-26 revision 15257) [i686-linux]  
00001  
0000  
…77

C e$B$G$O!"e(B(C e$B$Ne(B %o e$B$OId9f$J$7$J$N$Ge(B 1, 0 e$B$K$D$$$Fe(B)  
e$B0J2\<$N$h$&e(B  
e$B$K$J$j$^$9!#e(B

% cat tst.c  
#include \<stdio.h\>

int main(int argc, char \*\*argv)  
{  
printf("%#6.4o\n", 1);  
printf("%#6.4o\n", 0);  
return 0;  
}

% gcc -Wall tst.c  
% ./a.out  
0001  
0000

width e$B$,e(B 6 e$B$J$N$Ge(B 6e$B7e$K$J$ke(B C  
e$B$N7k2L$,E,@Z$@$H;W$$$^$9!#e(B  
e$B$=$l$H$N0l4S@-$+$i$7$F!“e(B-1 e$B$N$H$-$Ne(B " …77” e$B$be(B  
6e$B7e$K$J$k$h$&e(B  
e$B6uGr$,$b$&$R$H$DI,MW$@$H;W$$$^$9!#e(B

e$B$^$?!“e(B1 e$B$r%U%)!\<%^%C%H$7$?7k2L$,e(B " 0001”  
e$B$K$J$k$N$O!"e(B8e$B?J$NBee(B  
e$BBX7A\<0$Oe(B precision e$B$rA}$d$9$h$&$JF0:n$G!“e(B1 e$B$N\>l9ge(B  
4e$B7e$G$9$Ge(B  
e$B$K@hF,$,e(B 0 e$B$J$N$Ge(B precision  
e$B$rA}$d$5$J$$$?$a$@$H;W$$$^$9!#5,e(B  
e$B3Je(B (ANSI C) e$B$K$O0J2\<$N$h$&$K=q$$$F$”$j$^$9!#e(B

```
   # The result is converted to an ``alternative form''.
         For o conversion, it increases the precision, if and
         only if necessary, to force the first digit of the
         result to be a zero (if the value and precision are
         both 0, a single 0 is printed).
```