Robert Gamble wrote:
jc**********@gmail.com wrote:
Is there a format specification for printf that will result in:
1000000 being printed as 1,000,000? Or 1000000.0 as 1,000,000.0?
See Question 12.11 on the FAQ, it was posted today and can be found
at http://www.eskimo.com/~scs/C-faq/top.html.
You may also use my coding:
#ifndef putnums_h_ /* --- file putnums.h --- */
# define putnums_h_
# ifdef __cplusplus
extern "C" {
# endif
/* Using binary as an example, code to ourput numbers
in a field, while injecting commas at intervals.
By C.B. Falconer. Put in public domain. 2003-02-15
*/
/* ------------------- */
/* Negative field for left justification, 0 based */
/* clump is interval for group separator, 0 for none */
int putnum(FILE *fp, long v, int base,
int field, int clump);
/* ------------------- */
/* Negative field for left justification, 0 based */
/* clump is interval for group separator, 0 for none */
int putunum(FILE *fp, unsigned long v, int base,
int field, int clump);
/* Macros to ease use for decimal output */
#define putdnum(fp, v, field, clump) \
putnum(fp, v, 10, field, clump)
#define putudnum(fp, v, field, clump) \
putunum(fp, v, 10, field, clump)
# ifdef __cplusplus
}
# endif
#endif
/* --- end putnums.h --- */
/* --- file putnums.c ---
Using binary as an example, code to ourput numbers
in a field, while injecting commas at intervals.
By C.B. Falconer. Put in public domain. 2003-02-15
*/
#include <stdio.h>
#include "putnums.h"
#ifdef TESTING /* Add in a demonstration driver */
# include <limits.h>
# define BASE 10 /* Try 2 through 16 here only */
# define GROUP 3 /* with 0, 4 or 3 here */
#endif
/* ------------------- */
/* The original call must pass in depth == 0 */
/* field is zero based, so 36 allows 37 chars */
static int putval(FILE *fp, unsigned long v, int base,
int field, int clump, int neg,
int depth)
{
int retval;
static char hexchars[16] = "0123456789abcdef";
if (depth && clump && ((depth % clump) == 0)) field--;
if ((v / base) > 0) {
retval = 1 + putval(fp, v/base, base, field,
clump, neg, depth+1);
}
else {
if (neg) field--;
while (field > depth) {
putc(' ', fp);
field--;
}
if (neg) {
putc('-', fp);
retval = 2;
}
else retval = 1;
}
/* Revise this for base value larger than 16 */
putc((v % base)[hexchars], fp);
if (depth && clump && ((depth % clump) == 0)) {
putc(',', fp);
retval++;
}
return retval;
} /* putval */
/* ------------------- */
/* Negative field for left justification, 0 based */
/* clump is interval for group separator, 0 for none */
int putnum(FILE *fp, long v, int base,
int field, int clump)
{
int retval;
if (v < 0) retval = putval(fp, -v, base, field, clump, 1, 0);
else retval = putval(fp, v, base, field, clump, 0, 0);
while ((field + retval) <= 0) {
field++;
putc(' ', fp);
}
return retval;
} /* putnum */
/* ------------------- */
/* Negative field for left justification, 0 based */
/* clump is interval for group separator, 0 for none */
int putunum(FILE *fp, unsigned long v, int base,
int field, int clump)
{
int retval;
retval = putval(fp, v, base, field, clump, 0, 0);
while ((field + retval) <= 0) {
field++;
putc(' ', fp);
}
return retval;
} /* putunum */
/* ------------------- */
#ifdef TESTING
int main(void)
{
int i, lgh;
for (i = 0; i < 50; i++) putchar('0' + i % 10);
putchar('\n');
for (i = 0; i < 12; i++) {
lgh = putnum(stdout, i, BASE, 36, GROUP);
putchar(' ');
lgh = putnum(stdout, lgh, BASE, 8, GROUP);
puts(".");
}
i = INT_MAX - 4;
do {
i++;
lgh = putnum(stdout, i, BASE, 36, GROUP);
putchar(' ');
lgh = putnum(stdout, lgh, BASE, 8, GROUP);
puts(".");
} while (i < INT_MAX);
i = INT_MIN + 4;
do {
i--;
lgh = putnum(stdout, i, BASE, 36, GROUP);
putchar(' ');
lgh = putnum(stdout, lgh, BASE, 8, GROUP);
puts(".");
lgh = putunum(stdout, (unsigned long)i, BASE, 36, 0);
putchar(' ');
lgh = putnum(stdout, lgh, BASE, 8, GROUP);
puts(".");
} while (i > INT_MIN);
lgh = putunum(stdout, 1, BASE, -36, GROUP);
putchar(' ');
lgh = putunum(stdout, lgh, BASE, 8, GROUP);
puts(".");
for (i = 0; i < 4; i++) {
lgh = putudnum(stdout, (unsigned long)-i, 36, GROUP);
putchar(' ');
lgh = putdnum(stdout, lgh, 8, GROUP);
puts(".");
lgh = putunum(stdout, (unsigned long)-i, 16, 36, 4);
putchar(' ');
lgh = putunum(stdout, lgh, BASE, -8, GROUP);
puts(".");
lgh = putunum(stdout, (unsigned long)-i, 2, -36, 4);
putchar(' ');
lgh = putunum(stdout, lgh, BASE, 8, GROUP);
puts(".");
}
return 0;
} /* main */
#endif
/* --- end putnums.c --- */
--
"I conclude that there are two ways of constructing a software
design: One way is to make it so simple that there are obviously
no deficiencies and the other way is to make it so complicated
that there are no obvious deficiencies." -- C. A. R. Hoare
