Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
418 views
in Technique[技术] by (71.8m points)

c - Simple program adding "D" to output

I have a very simple program that just prints the number of newlines as an integer and I get a "D" after every number.

Sample input:
d [enter]
e [enter]
f [enter]
Ctrl-D [enter]

Sample output:
3D

What am I doing wrong?

This is verbatim from The C Programming Language 2nd edition, pg. 19:

#include <stdio.h>

main()  
{  
    int c, nl;  
    nl = 0;

    while ((c = getchar()) != EOF)  
        if (c == '
')  
            ++nl;  
    printf("%d
", nl);  
}
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

I think the D comes from the Ctrl D. The console outputs ^D as its standard echo logic, prior to passing the corresponding char (or rather here lack of char, i.e. EOF status) to getchar(), however, and rightfully, not sending a cr/lf. The C program then sends its 3, et voila...

Try the program by typing more than 9 CR before exiting and the problem should "go away", i.e. not show.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...