Printing leading 0's in C?

Question

I\'m trying to find a good way to print leading 0\'s, such as 01001 for a zipcode. While the number would be stored as 1001, what is a good way to do it?

I thought

Answer 1

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.

Answer 2

You place a zero before the minimum field width:

printf("%05d",zipcode);

Answer 3

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.

Answer 4

printf allows various formatting options.

ex:

printf("leading zeros %05d", 123);

Answer 5

sprintf(mystring, "%05d", myInt);

Here, "05" says "use 5 digits with leading zeros".

Answer 6

printf("%05d", zipCode);

The 0 indicates what you are padding with and the 5 shows the length of the integer number. For example if you use "%02d" (Useful for dates) this would only pad zeros for numbers in the ones column ie.(06 instead of 6). Example 2, "%03d" would pad 2 zeros for one number in the ones column and pad 1 zero for a number in the tens column. ie. (number 7 padded to 007 and number 17 padded to 017).