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Loop and getchar problems

Hi,

I'm a newbie programmer. I can't get work the following code.

/*
Objective:

Use a loop to print out all of the input characters until a newline is
found.

*/
#include <stdio.h>

int main (){
/* Declare variable, Assign a initial value x. */
char a = 'x';

while (a != '\n') {
/* Get a user input */
a = getchar();

if (a == '\n'){
/* If the input is a new line, say good bye to user */
printf("\nThat' s it for today.\n");

} else {
/* Prints a user input */
printf("%c",a);
}

}

return 1;
}

Jun 1 '07 #1
14 3085
Tak
On 6ÔÂ1ÈÕ, ÏÂÎç5ʱ25·Ö, Samuel.Codd...@ gmail.com wrote:
Hi,

I'm a newbie programmer. I can't get work the following code.

/*
Objective:

Use a loop to print out all of the input characters until a newline is
found.

*/

#include <stdio.h>

int main (){
/* Declare variable, Assign a initial value x. */
char a = 'x';

while (a != '\n') {

/* Get a user input */
a = getchar();

if (a == '\n'){
/* If the input is a new line, say good bye to user */
printf("\nThat' s it for today.\n");

} else {
/* Prints a user input */
printf("%c",a);
}

}

return 1;

}
It's my program:
#include <stdio.h>

int main (){
char a;

while ((a = getchar()) != '\n') {
printf("%c",a);
}
printf("\nThat' s it for today.\n");

return 1;
}

right??????

Jun 1 '07 #2
On 1 Jun, 10:25, Samuel.Codd...@ gmail.com wrote:
Hi,

I'm a newbie programmer. I can't get work the following code.
"I can't get work" doesn't tell me much about your problem.

Generally if there's a problem you need help with, it's helpful to
tell us
* What did you expect to happen?
* What did happen?

Your code works for me, and behaves exactly as I expect, but that's
not necessarily what you expected, so you probably need to tell us
what you expected.

I'll give you a hint - standard input is probably line-buffered...
>
/*
Objective:

Use a loop to print out all of the input characters until a newline is
found.

*/

#include <stdio.h>

int main (){
/* Declare variable, Assign a initial value x. */
char a = 'x';

while (a != '\n') {

/* Get a user input */
a = getchar();

if (a == '\n'){
/* If the input is a new line, say good bye to user */
printf("\nThat' s it for today.\n");

} else {
/* Prints a user input */
printf("%c",a);
}

}

return 1;

}

Jun 1 '07 #3
Sa************@ gmail.com wrote:

Minor notes (since Mark has started the major ones):
#include <stdio.h>

int main (){
/* Declare variable, Assign a initial value x. */
Pointless comment.
char a = 'x';

while (a != '\n') {
/* Get a user input */
Ditto.
a = getchar();
`getchar` returns `int`. So `a` should be `int`. (This is because
the result of `getchar` has to allow for every character /and/
EOF.)

(fx:snip)
return 1;
Not portable. 0, EXIT_SUCCESS, EXIT_FAILURE (those from stdlib)
are portable.
}
--
"- born in the lab under strict supervision -", - Magenta, /Genetesis/

Hewlett-Packard Limited Cain Road, Bracknell, registered no:
registered office: Berks RG12 1HN 690597 England

Jun 1 '07 #4
Hi, Tak,

Your code is much clearner. But the result on my end is the same.

I wanna make the program so that the program prints all the inputs
until a user input a new like (generally by pressing return).

So, it should open for a new input.
That string "That's it for today" should be displayed only when a user
type a newline.

Jun 1 '07 #5
Tak said:
It's my program:
#include <stdio.h>

int main (){
char a;

while ((a = getchar()) != '\n') {
printf("%c",a);
}
printf("\nThat' s it for today.\n");

return 1;
}

right??????
Wrong. Well, you're right that it's your program, but you're wrong that
it's right. It's wrong.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.
Jun 1 '07 #6
On 1 Jun, 10:53, mark_blue...@po box.com wrote:
On 1 Jun, 10:25, Samuel.Codd...@ gmail.com wrote:
Hi,
I'm a newbie programmer. I can't get work the following code.

"I can't get work" doesn't tell me much about your problem.

Generally if there's a problem you need help with, it's helpful to
tell us
* What did you expect to happen?
* What did happen?

Your code works for me, and behaves exactly as I expect, but that's
not necessarily what you expected, so you probably need to tell us
what you expected.
[Snip]

I'd better qualify my comments by saying that I didn't bother with the
nitpicking about whether you should declare main as "int main(void)"
or that a should be an int.

Jun 1 '07 #7
ma**********@po box.com said:
On 1 Jun, 10:25, Samuel.Codd...@ gmail.com wrote:
>Hi,

I'm a newbie programmer. I can't get work the following code.

"I can't get work" doesn't tell me much about your problem.
Actually, I think it tells you all you need to know.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.
Jun 1 '07 #8
Sa************@ gmail.com said:
Hi,

I'm a newbie programmer. I can't get work the following code.
Here's your program again, properly indented for readability:

#include <stdio.h>

int main()
{
/* Declare variable, Assign a initial value x. */
char a = 'x';

while(a != '\n')
{
/* Get a user input */
a = getchar();

if(a == '\n')
{
/* If the input is a new line, say good bye to user */
printf("\nThat' s it for today.\n");
}
else
{
/* Prints a user input */
printf("%c", a);
}
}

return 1;
}

Problems:

1) a has a lousy name!
2) a has the wrong type - it should be int.

Whilst I wouldn't want to suggest that your program is otherwise devoid
of problems, it does appear to do what is asked of it, except in cases
where it hits the end-of-file, where it does get a bit messy, but you
presumably aren't worried about that.

For the record, here's how I'd have written it:

#include <stdio.h>

int main(void)
{
int ch = 0;
while((ch = getchar()) != EOF && ch != '\n')
{
putchar(ch);
}

printf("\nThat' s it for today.\n");

return 0;
}

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.
Jun 1 '07 #9
On 1 Jun, 11:27, Richard Heathfield <r...@see.sig.i nvalidwrote:
mark_blue...@po box.com said:
On 1 Jun, 10:25, Samuel.Codd...@ gmail.com wrote:
Hi,
I'm a newbie programmer. I can't get work the following code.
"I can't get work" doesn't tell me much about your problem.

Actually, I think it tells you all you need to know.
Meow! Harsh but essentially fair, I guess.

However, he did post a complete, compilable, relatively cleanly
formatted program - give him some points for that...

Jun 1 '07 #10

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