interesting C program

[prady]

hi all,

could any one solve the following C program. If any one knows the
answer please post it

Ques:

A C function that will print 1 to N one per each line on the
stdout , where N is a int parameter to the function. The function
should not
use while, for, do-while loops, goto statement, recursion, and switch
statement.

 

[santosh]

hi all,

could any one solve the following C program. If any one knows the
answer please post it

This is not a homework group.

<snip absurd exercise>

 

[Mark Bluemel]

Previous on Buffy the Vampire Slayer, oops I meant,

hi all,

could any one solve the following C program. If any one knows the
answer please post it

Ques:

A C function that will print 1 to N one per each line on the
stdout , where N is a int parameter to the function. The function
should not
use while, for, do-while loops, goto statement, recursion, and switch
statement.

This was discussed a while back, I personally can't see the point of the
question. I expect some perverted mind will come up with a solution, but
I wouldn't be surprised to find their solution flawed/non-portable.

 

[daya]

int PRINT (int N)
{
if(N>0)
PRINT (N-1);
printf("%d\n",N);
return 0;
}

 

[Chris Dollin]

Previous on Buffy the Vampire Slayer, oops I meant,


This was discussed a while back, I personally can't see the point of the
question.

To make the student thing & explore the possibilities ...

I expect some perverted mind will come up with a solution,

Thank you, kind sir.

but I wouldn't be surprised to find their solution flawed/non-portable.

Actually I believe it's portable and completely straightforward. Also
an utterly stupid way of printing 1-to-N lines, but that's a different
issue.

Note that I'm not saying what the solution /is/, since I too believe
that Prady will get more benefit from working out the solution themself
than from having one of us provide it.

Here's a clue: it requires functions from C's standard library.

 

[Chris Dollin]

int PRINT (int N)
{
if(N>0)
PRINT (N-1);
printf("%d\n",N);
return 0;
}

What part of "The function should not use while, for, do-while loops,
goto statement, /recursion/, and switch statement" [emphasis mine]
don't you understand?

[Why is `PRINT` spelled with CAPS when it's not a MACRO?]

 

[Richard Tobin]

[...]

Actually I believe it's portable and completely straightforward. Also
an utterly stupid way of printing 1-to-N lines, but that's a different
issue.[/QUOTE]

Can you see any point to the prohibition of switch statements?

-- Richard

 

[Rachael]

There's the silly solution:

int i=1;
/* and then write out INT_MAX times: */
if (i<=N) {
printf("%d\n",i);
i++;
}

I once failed an interview question very similar to this, because I
couldn't imagine they were looking for such an inelegant "solution",
but they were.

 

[Richard]

A C function that will print 1 to N one per each line on the
stdout , where N is a int parameter to the function. The function
should not
use while, for, do-while loops, goto statement, recursion, and switch
statement.

[...]

Actually I believe it's portable and completely straightforward. Also
an utterly stupid way of printing 1-to-N lines, but that's a different
issue.

Can you see any point to the prohibition of switch statements?

-- Richard[/QUOTE]

To encourage students to think "out of the box" pretty much like any
teaching course. Most exercises given on courses have almost no
practical usage in their own right. The idea is to stimulate the student
into thinking about the language and it's features.

 

[Richard]

There's the silly solution:

int i=1;
/* and then write out INT_MAX times: */
if (i<=N) {
printf("%d\n",i);
i++;
}

I once failed an interview question very similar to this, because I
couldn't imagine they were looking for such an inelegant "solution",
but they were.

I'd love to see some of the questions that a few of the core members of
this group would set the hapless interviewees :-;

 

[Ben Pfaff]

There's the silly solution:

int i=1;
/* and then write out INT_MAX times: */
if (i<=N) {
printf("%d\n",i);
i++;
}

Why use a variable then?

if (i <= 1)
puts("1");
if (i <= 2)
puts("2");
if (i <= 3)
puts("3");
....

 

[Chris Dollin]

A C function that will print 1 to N one per each line on the
stdout , where N is a int parameter to the function. The function
should not
use while, for, do-while loops, goto statement, recursion, and switch
statement.

[...]

Actually I believe it's portable and completely straightforward. Also
an utterly stupid way of printing 1-to-N lines, but that's a different
issue.

Can you see any point to the prohibition of switch statements?[/QUOTE]

It might be to prevent the student from wasting their time thinking of a
way of using them; otherwise, no.

[I've now managed to turn my insight into code. Perhaps "completely
straightforward" was a little optimistic, eg there's an `if` in there
whose condition is always true ... I think there's room for improvement.]

 

[Ben Pfaff]

A C function that will print 1 to N one per each line on the
stdout , where N is a int parameter to the function. The
function should not use while, for, do-while loops, goto
statement, recursion, and switch statement.

Need it be portable?

void function(int n)
{
char cmd[64];
sprintf(cmd, "seq %d", n);
system(cmd);
}

 

[Chris Dollin]

[I've now managed to turn my insight into code. Perhaps "completely
straightforward" was a little optimistic, eg there's an `if` in there
whose condition is always true ... I think there's room for improvement.]

There was.

Shiny! That fixed the 0 case, too!

 

[Richard]

Why use a variable then?

if (i <= 1)
puts("1");
if (i <= 2)
puts("2");
if (i <= 3)
puts("3");
...

Because for a program which covers all integers from 0 to MAX_INT N is
the cut off.

 

[Rachael]

Why use a variable then?

if (i <= 1)
puts("1");
if (i <= 2)
puts("2");
if (i <= 3)
puts("3");
...

Assuming you mean
if (N >= 1)
then yes, you're right.

 

[Philip Potter]

A C function that will print 1 to N one per each line on the
stdout , where N is a int parameter to the function. The
function should not use while, for, do-while loops, goto
statement, recursion, and switch statement.

Need it be portable?

void function(int n)
{
char cmd[64];
sprintf(cmd, "seq %d", n);
system(cmd);
}

If you're not worried about portability, then look at my program:

void _G(int n);

void f(int n) {
_G(n);
}

Naturally, _G() is to be provided by the implementation.

 

[Duncan Muirhead]

hi all,

could any one solve the following C program. If any one knows the
answer please post it

Ques:

A C function that will print 1 to N one per each line on the
stdout , where N is a int parameter to the function. The function
should not
use while, for, do-while loops, goto statement, recursion, and switch
statement.

Hint: look up the standard library functions setjmp and longjmp.

 

[Johannes Bauer]

There's the silly solution:

[Snip]

That's what I thought first, but couldn't really believe they were
asking for that.

I once failed an interview question very similar to this, because I
couldn't imagine they were looking for such an inelegant "solution",
but they were.

Most braindead assignment *ever*, seriously. Whoever asks these
questions should not be allowed to teach/have a leading position in HR.
BTW, did you get the job anyways?

Greetings,
Johannes

 

[Rachael]

Most braindead assignment *ever*, seriously. Whoever asks these
questions should not be allowed to teach/have a leading position in HR.
BTW, did you get the job anyways?

The other questions in the interview were very interesting. I think
with that question they wanted to see whether I was blind to the
"braindead" solution when there were no other options.
I didn't get the job, but it's OK, because it was about an hour away
by train and my current job is 15 minutes away by bike