From: lew.pitcher@digitalfreehold.ca
On Fri, 06 Mar 2026 17:38:04 +0000, Lew Pitcher wrote:
> On Fri, 06 Mar 2026 10:36:19 -0500, DFS wrote:
>
>> On 2/26/2026 2:34 PM, Lew Pitcher wrote:
>>
>>
>>> static void dosquare(unsigned int n_rows, unsigned int n_cols, unsigned
int cut_off)
>>> {
>>> unsigned int field_width; /* for equal spacing of output data */
>>>
>>> if (cut_off == 0) cut_off = n_rows * n_cols;
>>> field_width = ceil(log10(cut_off)) + 1;
>>>
>>> for (unsigned int row = 0; row < n_rows; ++row)
>>> {
>>> for (unsigned int col = 0; col < n_cols; ++col)
>>> {
>>> unsigned int valu = 1 + row + (col * n_rows);
>>> if (valu <= cut_off)
>>> printf("%-*u",field_width,valu);
>>> }
>>> puts("");
>>> }
>>> }
>>
>>
>> I found a nit:
>>
>> with 1-column inputs like 10 1 3 or 100 1 25, your program prints (row
>> - cutoff) blank lines after the cutoff.
> [snip]
>
> Yes, I'm aware :-)
>
> I fixed it in a later version, which I have not posted yet.
And, here it is...
/*
** From: DFS
** Newsgroups: comp.lang.c
** Subject: Sort of trivial code challenge - may be interesting to you anyway
** Date: Thu, 19 Feb 2026 16:55:25 -0500
** Message-ID: <10n80sc$3soe4$1@dont-email.me>
**
** Challenge is to output sequential numbers by column then row:
** Kind of goes without saying the solution should handle any row x column
** input:
**
** input rows columns
** --------------------------------------------------------------------
** 1) must be able to cut the output off at any arbitrary value
** lower than rows x columns
** --------------------------------------------------------------------
** 2) if you don't specify rows and columns, your solution must try
** to calculate them to form a square (same # of rows and columns)
** that includes only 1 to N.
**
** If rows=columns can't be calculated, return message 'not possible'
** --------------------------------------------------------------------
**
** * Extra Credit if you determine a formula for this requirement. I kind
** of brute-forced it with 2 loops. As you can see, N = prime isn't
** enough to know if it can be done.
** -----------------------------------------------------------------------
**
** From: Tim Rentsch
** Newsgroups: comp.lang.c
** Subject: Re: Sort of trivial code challenge - may be interesting to you
anyway
** Date: Mon, 02 Mar 2026 00:44:57 -0800
** Message-ID: <86v7feei2e.fsf@linuxsc.com>
**
** Here is a counter challenge to make things more interesting: as above,
** but don't use nested loops (or goto's, etc).
**
** -----------------------------------------------------------------------
**
** From: Michael S
** Newsgroups: comp.lang.c
** Subject: Re: Sort of trivial code challenge - may be interesting to you
anyway
** Date: Mon, 2 Mar 2026 11:07:20 +0200
** Message-ID: <20260302110720.00007698@yahoo.com>
**
** Another counter challenge could have been to commpletely avoid loops/goto.
**
** ==========================================================================
**
** DFS challenge; solution by Lew Pitcher 2026-02-26
** cc -o rowcol_CLC -mtune=native -Wall -std=c99 -pedantic -lm rowcol_CLC.c
**
** Tim Rentsch counter-challenge; solution by Lew Pitcher 2026-03-03
** cc -o rowcol_CLC -mtune=native -Wall -std=c99 -pedantic -lm -
NO_NESTED_LOOPS rowcol_CLC.c
**
** Michael S counter-challenge; solution by Lew Pitcher 2026-03-03
** cc -o rowcol_CLC -mtune=native -Wall -std=c99 -pedantic -lm -DNO_LOOPS
rowcol_CLC.c
**
** NB: solutions use ceil(), sqrt(), and log10() calls from math lib
**
** This code released into the public domain. Lew Pitcher, 2026-03-04
*/
#include
#include
#include
#include
/*
** define RIGHT_ALIGN to right-align all numeric results
** otherwise, numeric results will align to the left
*/
#ifdef RIGHT_ALIGN
#define FORMAT "%*u"
#else
#define FORMAT "%-*u"
#endif
static int StrUint(const char *string, unsigned int *valu);
static void dosquare(unsigned int n_rows, unsigned int n_cols, unsigned int
cut_off);
int main(int argc, char *argv[])
{
int status = EXIT_FAILURE,
args_ok = 1;
unsigned int n_rows = 0,
n_cols = 0,
cut_off = 0;
switch (argc)
{
case 4: /* rowcol #rows #cols cutoff */
if ((StrUint(argv[3],&cut_off) == 0) || (cut_off == 0))
{
fprintf(stderr,"Invalid value for cut-off (\"%s\")\n",argv[3]);
args_ok = 0;
}
case 3: /* rowcol #rows #cols */
if ((StrUint(argv[1],&n_rows) == 0) || (n_rows == 0))
{
fprintf(stderr,"Invalid value for # rows (\"%s\")\n",argv[1]);
args_ok = 0;
}
if ((StrUint(argv[2],&n_cols) == 0) || (n_cols == 0))
{
fprintf(stderr,"Invalid value for # columns (\"%s\")\n",argv[2]);
args_ok = 0;
}
/* cut-off value must occur within table bounds */
if (cut_off)
{
if (cut_off > n_rows * n_cols)
{
fprintf(stderr,"cut off value %u not found in table\n",cut_off);
args_ok = 0;
}
}
else cut_off = n_rows * n_cols;
break;
case 2: /* rowcol cutoff */
if ((StrUint(argv[1],&cut_off) == 0) || (cut_off == 0))
{
fprintf(stderr,"Invalid value for cut off (\"%s\")\n",argv[1]);
args_ok = 0;
}
else
{
/*
** Compute n_rows and n_cols, and validate that cut_off
** value occurs as last entry in final column
**
** ----- Narrative -----
** As problem definition states that, for this configuration,
** n_rows must equal n_cols, and that n_rows * n_cols must
** include the cut_off value, we first approximate the value
** of n_rows and n_cols by taking the square root of cut_off
** and rounding that value up to the nearest integer. This
** guarantees that n_rows * n_cols is the smallest square
** that will contain the cut_off value.
**
** But, this rounded value might be too big to place cut_off
** in the last column. So, we compute the first entry in
** the last column, and make sure that cut_off is not less
** than that value (if it is, then cut_off occurs in a column
** prior to the last column, and violates the constraints
** of this configuration).
**
** FWIW, because of the way we compute n_rows and n_cols,
** we know that cut_off will never /exceed/ n_rows * n_cols.
*/
n_rows = n_cols = ceil(sqrt(cut_off));
if ( (cut_off < (n_rows * (n_cols-1)) + 1) )
{
fprintf(stderr,"Cut off value %u not possible where rows=cols\n",cut_off);
args_ok = 0;
}
}
break;
default:
args_ok = 0; /* default error msg is usage message */
[continued in next message]
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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