looping

I can't get my program to loop properly. Here's the code:

#include <stdio.h>

main()

{
char a;

printf("Enter a letter\n");

for ( ; ; )

scanf("%c",&a);

printf("\nThe decimal value of the character you entered is %d\n\n",a);


}


What am I doing wrong?

Perhaps something more like this is what you want:

Code:

---

#include <stdio.h>

int main(void)
{
  char a;
 
  printf("Enter a letter\n");
 
  for ( ; ; ) {
    scanf("%c%*c",&a);
    printf("\nThe decimal value of the character you entered is %d\n\n",a);
  }
 
  return 0;
}

---

Multiline loops must be surrounded by a block.

-Prelude

i dont want to hijack this thread but i always wondered what
that

Code:

---

for ( ; ; )

---

statement actually does.
anyone?

thanks

it's an infinate loop. you can leave out any of the paremetes(?) of a for statement.. if you have nothing to stop the loop (the second paremeter) then it never stops.. putting the other two in is then pointless, so you do for( ; ; ) for an infinate loop.

>anyone?
It's an infinite loop, there's no condition to stop it and no need for initialization or modification of a counter.

-Prelude

Why does the scanf statement have to be scanf("%c%*c",&a); instead of scanf("%c",&a);?

>Why does the scanf statement have to be scanf("%c%*c",&a); instead of scanf("%c",&a);?
Because otherwise you'll loop twice for each letter, once for the letter and once for the return key. The %*c flag tells scanf to read a single character and discard it. Since we know it's the return key we can safely get rid of it for the sake of pretty output.

-Prelude

Quote:

---

Originally posted by MadHatter
it's an infinate loop. you can leave out any of the paremetes(?) of a for statement.. if you have nothing to stop the loop (the second paremeter) then it never stops.. putting the other two in is then pointless, so you do for( ; ; ) for an infinate loop.

---

Yes, but the real question is: which is better? while(1) or for( ; ; )? I'm sure there will be a huge debate about this on the General Discussions board.

Quote:

---

Yes, but the real question is: which is better? while(1) or for( ; ; )? I'm sure there will be a huge debate about this on the General Discussions board.

---

for(; ; ) = We haven't any condition here, so I don't think that the computer every time check the condition.

while(1) = We have a condition here, so the computer will check always the condition (or not?).


I really don't no if in this case:

Code:

---

for(; ; ) {
    printf("Blah");
    printf("\nBleh");
  a = b*b;
}

---

The computer check any condition....
He just jump to the start, right?

I don't think that for(; ; ) is better than while(1) and vice-versa.

while(1) is 8 letters
for( ; ; ) is 7 letters...

:D

I think that it takes around a nanosecond shorter for me to understand what while(TRUE) is doing, than for(;;) so I use the while statement. It look better too.

Quote:

---

Originally posted by C-learning
while(1) is 8 letters
for( ; ; ) is 7 letters...

:D

---

You had to hit 10 keys to write for( ; ; ) and only 8 to write while(1)

:D

Thats true.
But i was never good at math...

:D

>which is better? while(1) or for( ; ; )?
It's a matter of preference, but

while ( 1 )

will often cause a warning about a constant loop condition while

for ( ; ; )

doesn't have this problem.

-Prelude

Quote:

---

You had to hit 10 keys to write for( ; ; ) and only 8 to write while(1)

---

you forgot the SHIFT :)
Look, you had to hit 12 keys hehe

SHIFT+9= (
SHIFT+0 = )

:p

Enough of the pointless comments. If you want this thread reopened, PM me or another mod...