after getch() the program ignores the if even after putting 1-6.

Question

I have a problem with my code. It always ignoring the if(userDigit<=6 && userDigit>=1).. Can someone tell me what is wrong here?

        for(i=0; i<4; i++)
        {
            userDigit=getch();
            putch(userDigit);

            if(userDigit<=6 && userDigit>=1)
            {
                //code              
            }
            else
            {
               correct=0;
            }                       
        }

        if(correct == 0)
        {
            printf("wrong");
            correct++;
        }

`getch` is returning character, not digit. So compare it with characters, not digits. — Eugene Sh., Dec 21 '17 at 16:57

Bathsheba · Answer 1 · 2017-12-21T17:11:59.067

1

getch() returns a int representing the encoded value of the input character, not the digit itself.

Fortunately the C standard allows you to write

userDigit = getch() - '0';

to transform to the actual numerical value of the digit. Any non-digit input will be outside the range (0 - 9). (For the avoidance of doubt '0' is an int type in C.)

Naturally that will break your putch function (crudely you could transform back by adding '0'), but I suspect you have it there for debugging purposes and you can safely remove it.

edited Dec 21 '17 at 17:11

answered Dec 21 '17 at 16:58

Bathsheba

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Code wouldn't even compile... -1 – Kamila Szewczyk Dec 21 '17 at 16:59
Do I need a coffee? – Bathsheba Dec 21 '17 at 17:00
Actually `getch()` returns an `int` not a `char` but that `int` is the ASCII code (or UTF-8 or other character code) for what was typed in. – JeremyP Dec 21 '17 at 17:00
You try tapping that one out on an iPhone ;-) – Bathsheba Dec 21 '17 at 17:01
@JeremyP: Indeed. Furthermore '0' is an `int` type in C – Bathsheba Dec 21 '17 at 17:01
@JeremyP: Touche. Coffee? – Bathsheba Dec 21 '17 at 17:02
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That's the advantage of a peer reviewed Q & A site. We aim for quality. I'll flog this until it's correct. – Bathsheba Dec 21 '17 at 17:03

Anton Malyshev · Answer 2 · 2017-12-21T17:28:28.213

1

Change

if(userDigit<=6 && userDigit>=1)

to

if(userDigit<='6' && userDigit>='1')

That will work because '0', '1', ... symbols have consequential ASCII codes so the comparisons are valid.

edited Dec 21 '17 at 17:28

answered Dec 21 '17 at 16:58

Anton Malyshev

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Any explaination, please? – Kamila Szewczyk Dec 21 '17 at 17:01
Explaination is already done in Bathsheba's answer. '0', '1', ... symbols have consequential codes so the comparisons are valid – Anton Malyshev Dec 21 '17 at 17:03
If so, you can remove answer (as question 'is already answered') – Kamila Szewczyk Dec 21 '17 at 17:04
I just think it's a nice way to change the code to work – Anton Malyshev Dec 21 '17 at 17:06
No, you should retain an answer. It's good to have a selection to choose from. SO works best that way. – Bathsheba Dec 21 '17 at 17:07
1

Yet improving the answer based on feedback is more than welcome. – Eugene Sh. Dec 21 '17 at 17:10
Absolutely. I personally don't see a problem with this answer. Although some explanation might be helpful. – Bathsheba Dec 21 '17 at 17:10
Added some explanation – Anton Malyshev Dec 21 '17 at 17:28

after getch() the program ignores the if even after putting 1-6.

2 Answers2