while loop not looping as intended

Tarts · 11-26-2003, 03:24 AM

This has me pretty baffled and I would like to know if I baffle easy.

Code:

#include <stdio.h>

int main()
{
        int nl, c, t = 0;
        nl = 0;
        while (t <= 10) {
                c = getchar();
                ++t;
                if (c == '\t')
                        ++nl;
        }
        printf("%d\n", nl);
        return 0;
}

This doesnt loop while 't' is less than or equal to 10, but it varies in results. Whats the reason?

Thanks, Tarts.

cxel91a · 11-26-2003, 03:52 AM

It does loop, but you must enter a character to continue. The value being stored in c is of type int and not a character. So your out put will be different.

Tarts · 11-26-2003, 04:30 AM

Quote:

Originally posted by cxel91a
It does loop, but you must enter a character to continue. The value being stored in c is of type int and not a character. So your out put will be different.

It does loop, but when I output the value of 't', it seems has it looped once before already...

Code:

[Mirrus][stratus][04:28:53][/Source][$] /Exec/new1
a
The value of 't' is 0
The value of 't' is 1
a
The value of 't' is 2
The value of 't' is 3
a
The value of 't' is 4
The value of 't' is 5
a
The value of 't' is 6
The value of 't' is 7
a
The value of 't' is 8
The value of 't' is 9
a
The value of 't' is 10
0
[Mirrus][stratus][04:29:01][/Source][$]

It guess it just reads once, loops, skips the call to 'getchar()' , loops again and reads again. I understand...sure I do.

jimveta · 11-26-2003, 06:39 AM

you're right, because getchar() reads *all* the bytes in a stream, including a newline

and that's why you see it done twice.

so for example, if you typed "1234567890" then enter, that will finish the loop off in one line.

jim mcnamara · 11-26-2003, 06:42 AM

Each character you enter, followed by a return = 2 characters

Tarts · 11-26-2003, 07:14 AM

I see! Thanks!

jim mcnamara · 11-26-2003, 09:45 AM

Avoid scanf() - for a lot of reasons. Use fgets() instead.

Tarts · 11-28-2003, 02:50 AM

Quote:

Originally posted by jim mcnamara
Avoid scanf() - for a lot of reasons. Use fgets() instead.

I do, and if I ever make a program of relevence I wouldnt use it, I would still like to fix its problems though, or write a similar(in some ways) function that doesnt store a newline.

Tarts