Problem with C loop !

linuxlover1 · 11-02-2006, 03:01 PM

Hello there.... I have a strange problem with loops in C.

Code:

#include <stdio.h>
int main() {
     char ch;
     while (1) {
         printf("Give char: "); scanf("%c",&ch);
         if (ch == 'q') break;
     }
}

The above loop prints
First line: Give char: <char>
Second Line: Give char: Give char: <char>
Third Line: Give char: Give char: <char>
.
.
.

Well my question is an obvius one. Why the program prints 2 times the "Give char:" in second, third......n line ??
And how i can fix that?

Thanx in Advance !!!

reddazz · 11-02-2006, 03:07 PM

The reason why the loop never ends is because the condition you set is always true. For a loop to finish, the condition has to be false at some point.

xhi · 11-02-2006, 03:25 PM

Quote:

Originally Posted by linuxlover1

Well my question is an obvius one. Why the program prints 2 times the "Give char:" in second, third......n line ??

when you are reading in from stdin a \n gets left in the buffer, you need to clear that. just call getchar() once after the call to scanf and that should do it..

Quote:

Originally Posted by reddazz

The reason why the loop never ends is because the condition you set is always true. For a loop to finish, the condition has to be false at some point.

did you over look the break in the loop..

reddazz · 11-02-2006, 03:32 PM

Quote:

Originally Posted by xhi

...did you over look the break in the loop..

My bad, it looks like I did.