Characters not read correctly by scanf()

[Srlancelot39]

This is a program I have written for a question in a lab. It gets a character from the user, displays it, passes it to a function that displays it, the function then returns the character after the user's character and this is printed from main(). My issue is that no matter what character I enter, it displays it as a space (except for the returned value from the function which is always some unexpected symbol). After some hours of testing, I think I have confirmed that it is an issue to do with scanf() (scanf_s() in my case specifically).

code:

/* Name:   Sean Sciberras Course: PRG155H Date:   March 12, 2014 Program Description: Passes a character to a function and returns the character after it. */ #include<stdio.h> #include<conio.h> //declare functions char function(char); //main program void main() {         char chr;         //get character from user         printf("Enter a character: ");         scanf_s("%c", &chr);         printf("\nYou entered '%c', printing it now from main().", chr);         //pass character to function         function(chr);         printf("\nThe following ASCII character is '%c', printing it now from main().", function(chr));         _getch(); } //function char function(char chr1) {         printf("\nYou entered '%c', printing it now from function().", chr1);         //return next character         return (chr1 + 1); }

Output:
Enter a character: a

You entered ' ', printing it now from main().
You entered ' ', printing it now from function().
You entered ' ', printing it now from function().
The following ASCII character is '☺', printing it now from main().


Thanks in advance!

[Insectoid]

Odd, it works fine for me (after commenting out _getch() and #include <conio.h>, since they don't exist on osx).

[nullptr]

I'm not sure what could be causing your issue, but you could try this as a solution:

code:

char chr;         //get character from user         printf("Enter a character: ");         char buf[2];         scanf_s("%1s", buf);         chr = buf[0];

[Srlancelot39]

@Insectoid Half of me feared that would be the case, the other half hoped it would be lol
I hope it works for my prof lol

@nullptr thanks for the help, but same output :s

wtf is going on lol
Anyone got Bill Gates' cell number on hand?...

EDIT:
Ok, I am 99.9% sure that the user input is not being read correctly.
If I insert

code:

chr = 'x';

after the user input is read, the program will display 'x' and then 'y', as it should.
I have tried using

code:

getch(chr);

code:

getch(&chr);

code:

_getch(chr);

and

code:

_getch(&chr);

...none of which work either. I am using _getch() because conio.h is requiring me to for some reason.

EDIT2:
Yes, I have tried using pointers. Exact same result.

EDIT3:
(very sorry for all the edits lol)
I am using Visual Studio - Professional 2013

[Dreadnought]

I'm pretty sure that _getch returns the character (rather than taking a reference).

code:

int _getch( void );

Source: http://msdn.microsoft.com/en-us/library/078sfkak.aspx

[Insectoid]

Quote:

I am using _getch() because conio.h is requiring me to for some reason.

Newer compilers (since 1989, so older compilers too) require this to comply with ANSI C standards.

[Srlancelot39]

Dreadnought wrote:

I'm pretty sure that _getch returns the character (rather than taking a reference).

According to the rest of the document, it seems like it takes input without echo.

http://msdn.microsoft.com/en-us/library/078sfkak.aspx wrote:

Gets a character from the console without echo.

Example

c:

// crt_getch.c // compile with: /c // This program reads characters from // the keyboard until it receives a 'Y' or 'y'.   #include <conio.h> #include <ctype.h> int main( void ) {    int ch;    _cputs( "Type 'Y' when finished typing keys: " );    do    {       ch = _getch();       ch = toupper( ch );    } while( ch != 'Y' );    _putch( ch );    _putch( '\r' );    // Carriage return    _putch( '\n' );    // Line feed  }

...I don't know, I'm confused as hell as to why I'm having this problem lol

Thanks for the help! I know this isn't the easiest of things to troubleshoot

[btiffin]

A little late perhaps, but from the original listing

code:

scanf_s("%c", &chr);

try

code:

scanf_s("%c", &chr, 1);

Secure scanf REQUIRES the length for char data. I think that's because people that work for Microsoft believe that wchar was a good idea.

Or ... avoid MS non-standard crap and try

code:

scanf("%1c", &chr);

Live free and die trying or Live easy and die pwned

Cheers

[Srlancelot39]

Thanks for your solution!
I no longer need this solved, but thanks anyways! Much appreciated

As for scanf_s, my compiler will not let me use scanf. I tried using it initially (as that is what we were taught), but my compiler gives me an error about security and suggests that I use scanf_s.

[btiffin]

Realizing that the immediate need is over, but, being old and crusty...

As far as I know, only Microsoft has deprecated the scanf function. It's still very much alive in C land.

If you ever need to do this again, try

code:

#define _CRT_SECURE_NO_DEPRECATE

at the top of the sources, then wield scanf like the big boys (hmm, or is that bug boys?).

Is scanf dangerous? Can be, but scanf_s isn't implemented very often outside Windows, so scanf_s is far less portable.

The MS tactic of embrace, enhance, extinguish is HIGHLY UNLIKELY to ever succeed when it comes to C.

Cheers

[Srlancelot39]

Sounds like a plan! Thanks!
I've heard of using
#define _CRT_SECURE_NO_DEPRECATE
before, so I'm sure I won't forget to try it out next chance I get.