split number problem

[nicolas]

Aim: scanf a number what random digit,split this number;

for example: input "5680"

output "5,6,8,0";


input "45"

output "4,5";

--


_________________________________________
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ÓÐÊÂÇëͬÎÒÁªÏµ£¬
MSN£º (e-mail address removed)


---------

 

[Nils Petter Vaskinn]

Aim: scanf a number what random digit,split this number;

This wouldn't by any chance happen to be your homework?



NPV

 

[Dimitris Mandalidis]

On Wed, 3 Sep 2003 15:05:30 +0800, nicolas wrote

Aim: scanf a number what random digit,split this number;

for example: input "5680"

That's easy :

scanf("%d", &number);
number_of_digits = (int) (log10(number))+1; /* include <math.h> link with -lm */
if ((string = malloc(number_of_digits + 1)) == NULL)
/* Error handling */
token = string;
for (i = number_of_digits - 1; i >= 0; --i)
{
*string++ = (int) (number / pow(10,i)) + '0';
number = number % (int) pow(10,i);
*string++ = ',';
}
*string = '\0';
printf("%s\n", token);

HTH
D.

 

[Morris Dovey]

Aim: scanf a number what random digit,split this number;

for example: input "5680"
output "5,6,8,0";

input "45"
output "4,5";

Nicolas...

If you preferred not to use the functions prototyped in math.h,
then you could do something like:

#include <stdio.h>
#include <stdlib.h>

char *unsigned_to_digits(unsigned n)
{ char *p;
unsigned digits = 0,copy = n;
do ++digits; while (n /= 10); /* */
if (p = malloc(2*digits))
{ p += 2*digits;
*--p = '\0';
do
{ *--p = '0' + copy % 10;
if (copy /= 10) *--p = ',';
} while (copy);
}
return p;
}

int main(void)
{ char *p;
unsigned value;
scanf("%u",&value);
puts((p = unsigned_to_digits(value)) ? p :
"malloc() failure");
return 0;
}

 

[LibraryUser]

Aim: scanf a number what random digit,split this number;

for example: input "5680"
output "5,6,8,0";

input "45"
output "4,5";

Don't use scanf, use getc and putc.

 

[Fred L. Kleinschmidt]

Don't use scanf, use getc and putc.

Kinda tough if I/O is the terminal. How about using gets() to get the
string, then use putc or printf to output.

 

[Steve Zimmerman]

> Aim: scanf a number what random digit,split this number;
>
> for example: input "5680"
>
> output "5,6,8,0";
>
>
> input "45"
>
> output "4,5";
>
> --
>
>
> _________________________________________
> ÎÒÈÈ°®ÉîÈëµÄÌÖÂÛ£¡
> ÓÐÊÂÇëͬÎÒÁªÏµ£¬
> MSN£º (e-mail address removed)
>
>
> ---------
>
>
>

This works, but it doesn't use scanf:

#include <stdio.h>

int read_line(char str[], int n);

int main()
{
char digits[100];
int how_many;
int i;

printf("Enter up to 100 digits: ");
how_many = read_line(digits, 100);

for(i = 0; i < (how_many - 1); i++)
printf("%c,", digits);

/* Print the last digit with no trailing comma: */
printf("%c", digits[how_many - 1]);

printf("\n");

return 0;
}

int read_line(char str[], int n)
{
char ch;
int i = 0;

while ((ch = getchar()) != '\n')
if (i < n)
str[i++] = ch;

str = '\0';
return i;
}

--Steve

 

[Arthur J. O'Dwyer]

Kinda tough if I/O is the terminal. How about using gets() to get the
string, then use putc or printf to output.

How about using getc and putc? (Because gets is evil, and printf is
useless in the context of this problem.)

Hint: If the user enters "47227", what's the output?
What's the fastest way to generate this output?

(Rhetorical hints, BTW. Please don't do the OP's homework any
more than we've already done... Nice "solutions," by the way,
guys!)

Oh, and probably the OP can't use getc IRL, because the teacher
has told them specifically to use scanf. (Not that scanf("%c")
behaves much differently to getc(stdin), of course...)

-Arthur

 

[Aishwarya]

Nicolas...

on a lighter note, are we "positive" /* */ that the input is an
unsigned integer to the base of 10 ?

 

[Serve La]

scanf("%d", &number);
number_of_digits = (int) (log10(number))+1; /* include <math.h> link

with -lm */

what should happen if you pass in zero or a negative value?

 

[Morris Dovey]

on a lighter note, are we "positive" /* */ that the input is an
unsigned integer to the base of 10 ?

Aishwarya...

Of course not; but I hesitate to provide complete, general
solutions to homework problems. /My/ aim was to provide the OP
with something he could understand and modify as necessary to
meet the requirements of his assignment - to provide help without
eliminating the need for effort from the student.

It's a difficult balance to achieve, sometimes. It's easy to
either say: "Do your own homework!" or to provide the complete
solution. I find it much more difficult (but enormously more
satisfying) to provide a rough solution framework that a student
can hack on.

The modifications necessary to handle signed ints aren't really
difficult; and if output radix is an issue, the OP forgot to
mention it; and will have to further (trivially) modify the code.

A loser will hand in my code and almost certainly be identified
as submitting someone else's work - or they'll recognize that the
solution is incomplete and disregard it altogether. A winner will
note the use of "unsigned", work to understand what I've done,
and puzzle out the necessary modifications - and thereby make the
resulting program a product of his own efforts.

I always hope for winners.

8^)

 

[nicolas]

I get many benefit for solution and mothod via this note...

thanks

----from Chinese best regard.

 

[Aishwarya]

Aishwarya...

Of course not; but I hesitate to provide complete, general
solutions to homework problems. /My/ aim was to provide the OP
with something he could understand and modify as necessary to
meet the requirements of his assignment - to provide help without
eliminating the need for effort from the student.

It's a difficult balance to achieve, sometimes. It's easy to
either say: "Do your own homework!" or to provide the complete
solution. I find it much more difficult (but enormously more
satisfying) to provide a rough solution framework that a student
can hack on.

The modifications necessary to handle signed ints aren't really
difficult; and if output radix is an issue, the OP forgot to
mention it; and will have to further (trivially) modify the code.

A loser will hand in my code and almost certainly be identified
as submitting someone else's work - or they'll recognize that the
solution is incomplete and disregard it altogether. A winner will
note the use of "unsigned", work to understand what I've done,
and puzzle out the necessary modifications - and thereby make the
resulting program a product of his own efforts.

I always hope for winners.

8^)

Morris,

I do appreciate and admire your thoughts. But as I said earlier, it
was just a light note there was certainly no offense intended ..

Cheers,

 

[Steve Zimmerman]

I get many benefit for solution and mothod via this note...

thanks

----from Chinese best regard.

You're welcome, Nicolas, and thank you for the question.
If you have any more questions, please send them in to
this group.

--Steve

 

[Morris Dovey]

there was certainly no offense intended ..

....and none was taken (I enjoyed your pun).

 

[Charles Richmond]

Aim: scanf a number what random digit,split this number;

for example: input "5680"

output "5,6,8,0";

input "45"

output "4,5";

Just input the number as a string, and scan down
the string with a "for" loop. Output each character
that is a number...

 

[Dave Thompson]

int read_line(char str[], int n)
{
char ch;
int i = 0;

while ((ch = getchar()) != '\n')
if (i < n)
str[i++] = ch;

Infinite loop if input EOF or error occurs.

str = '\0';

Stores out of bounds (causing Undefined Behavior) if input provides n
or more characters in one line.

return i;
}

--Steve

- David.Thompson1 at worldnet.att.net