Printing leading 0 s in C

Question

I m trying to find a good way to print leading 0  such as 01001 for a ZIP Code  While the number would be stored as 1001  what is a good way to do it  I thought of using either case statements or if to figure out how many digits the number is and then convert it to an char array with extra 0 s for printing  but I can t help but think there may be a way to do this with the printf format syntax that is eluding me

User · Answer

You place a zero before the minimum field width  printf  quot  05d quot   zipcode

User · Answer

ZIP Code is a highly localised field  and many countries have characters in their postcodes  e g   UK  Canada  Therefore  in this example  you should use a string   varchar field to store it if at any point you would be shipping or getting users  customers  clients  etc  from other countries  However  in the general case  you should use the recommended answer  printf  quot  05d quot   number

User · Answer

More flexible    Here s an example printing rows of right-justified numbers with fixed widths  and space-padding     ---- Header std  string getFmt   int wid  long val         char buf 64     sprintf   buf      ld   wid  val      return buf     define FMT  getFmt 8 x  c str       ---- Put to use printf          COUNT     USED     FREE n     printf    A   s  s  s n   FMT C 0    FMT U 0    FMT F 0      printf    B   s  s  s n   FMT C 1    FMT U 1    FMT F 1      printf    C   s  s  s n   FMT C 2    FMT U 2    FMT F 2         -------- Output       COUNT     USED     FREE A       354   148523     3283 B  54138259 12392759   200391 C     91239     3281    61423   The function and macro are designed so the printfs are more readable

User · Answer

printf allows various formatting options  Example  printf  quot leading zeros  05d quot   123

User · Answer

printf  quot  05d quot   zipCode    The 0 indicates what you are padding with and the 5 shows the width of the integer number  Example 1  If you use  quot  02d quot   useful for dates  this would only pad zeros for numbers in the ones column  E g   06 instead of 6  Example 2   quot  03d quot  would pad 2 zeros for one number in the ones column and pad 1 zero for a number in the tens column  E g   number 7 padded to 007 and number 17 padded to 017

User · Answer

If you need to store the ZIP Code in a character array  zipcode    you can use this  snprintf zipcode  6   quot  05 5d quot   atoi zipcode

User · Answer

You will save yourself a heap of trouble  long term  if you store a ZIP Code as a character string  which it is  rather than a number  which it is not

User · Answer

sprintf mystring    05d   myInt     Here   05  says  use 5 digits with leading zeros

User · Answer

The correct solution is to store the ZIP Code in the database as a STRING   Despite the fact that it may look like a number  it isn t   It s a code  where each part has meaning  A number is a thing you do arithmetic on  A ZIP Code is not that

User · Answer

If you are on a  nix machine  man 3 printf  This will show a manual page  similar to   0      The value should be zero padded   For d  i  o  u  x  X  a  A  e  E  f  F  g  and G conversions  the converted value is padded  on the  left  with  zeros rather than blanks   If the 0 and - flags both appear  the 0 flag is ignored   If  a  precision  is  given with  a numeric conversion  d  i  o  u  x  and X   the 0 flag is ignored   For other conversions  the behavior is undefined   Even though the question is for C  this page may be of aid

User · Answer

There are 2 ways to output your number with leading zeroes  Using the 0 flag and the width specifier  int zipcode   123  printf  quot  05d n quot   zipcode       outputs 00123  Using the precision specifier  int zipcode   123  printf  quot   5d n quot   zipcode       outputs 00123  The difference between these is the handling of negative numbers  printf  quot  05d n quot   -123       outputs -0123  pad to 5 characters  printf  quot   5d n quot   -123       outputs -00123  pad to 5 digits   Zip codes are unlikely to be negative  so it should not matter  Note however that zip codes may actually contain letters and dashes  so they should be stored as strings  Including the leading zeroes in the string is straightforward so it solves your problem in a much simpler way  Note that in both examples above  the 5 width or precision values can be specified as an int argument  int width   5  printf  quot  0 d n quot   width  123       outputs 00123 printf  quot    d n quot   width  123       outputs 00123  There is one more trick to know  a precision of 0 causes no output for the value 0  printf  quot   0d  0d  n quot   0  1       outputs  0 1  printf  quot    0d   0d  n quot   0  1       outputs   1

[c] Printing leading 0's in C

Examples related to c

Examples related to printf