why the below code keep printing the value10?

Question

I was going to make a loop that if I type the alphabet then the ascii value comes out. Unless I type '0' in.

but result is as below. There is the code that I made below the result. Where the value 10 is coming from?

Press any Alphabet A 65 Press any Alphabet 10 Press any Alphabet

char aski;
while(1) 
{
    printf("Press any Alphabet\n");
    scanf("%c", &aski);
    if (aski == '0') 
        break;
    else
        printf("%d\n", aski);
}

The value `10` happens to be the ASCII encoding for newline `'\n'`. Now think a little why you might be getting newlines as input... — Some programmer dude, Nov 20 '20 at 13:48

Krishna Kanth Yenumula · Answer 1 · 2020-11-20T14:10:02.713

scanf reads an extra \n. ASCII of \n is 10. That's why you get 10. I suggest you to use getchar() to read extra \n.

#include <stdio.h>
int main()
{
    char aski;
    while (1)
    {
        printf("Press any Alphabet\n");
        scanf("%c", &aski);
        getchar();
        if (aski == '0')
            break;
        else
            printf("%d\n", aski);
    }

    return 0;
}

The output is:

Press any Alphabet
a
97
Press any Alphabet
b
98

PS: I stopped excution after, entering b.

score 0 · Answer 2 · answered Nov 20 '20 at 13:54

0

When you are pressing enter you are in fact creating a \n (new line) This char has the value of 10, which is what is being printed.

char c = '\n';
printf("%d",c);

Would give you 10 as result.

Try this

char aski;
scanf("%c ", &aski);

Notice the space after the %c, this makes sure to read all whitespace inputted.

answered Nov 20 '20 at 13:54

Sigurd

21
4

Please see this https://stackoverflow.com/questions/19499060/what-is-the-effect-of-trailing-white-space-in-a-scanf-format-string#:~:text=scanf()%20essentially%20skips%20over,so%20it's%20of%20little%20consequence. – Krishna Kanth Yenumula Nov 20 '20 at 14:01
`scanf("%c ", &aski);` this is not good practice. See the above link. – Krishna Kanth Yenumula Nov 20 '20 at 14:02
1

The space should go before the `%c`, not after, or it will wait for an extra input. – interjay Nov 20 '20 at 14:04
You guys are correct, a quick brain fart on my end :) – Sigurd Nov 20 '20 at 14:07

why the below code keep printing the value10?

2 Answers2