get_string function prints out special characters instead of the given prompt

[Senya247]

Here's my simple code-

I compile it with clang -lcs50 test2.c -o hello it generates no errors, but generates these warnings-

test2.c:6:16: warning: implicit declaration of function 'get_string' is invalid in C99 [-Wimplicit-function-declaration] string s = get_string("Input: "); ^ test2.c:6:12: warning: incompatible integer to pointer conversion initializing 'string' (aka 'char *') with an expression of type 'int' [-Wint-conversion] string s = get_string("Input: "); ^ ~~~~~~~~~~~~~~~~~~~~~ 2 warnings generated.

then when i execute it with ./hello, i get this weird prompt this peice of code works fine on the online cs50 ide, so something must be wrong on my computer. Here's my computer's info- I'd installed the library with $ curl -s https://packagecloud.io/install/repositories/cs50/repo/script.deb.sh | sudo bash $ sudo apt-get install libcs50 How do I fix this?

[nuoxoxo]

You have compiled the code with -o. As a result, hello will be an object.

When you print an object out, it displays the machine language, hence the "special characters".

I think you can try again and compile it using make since you have the libcs50.

[dmalan]

@Nightmare247, sure you didn't take any other steps (e.g., manually editing cs50.h once installed)? I just did

$ docker run -it ubuntu:20.10
$ apt-get update
$ apt-get install -y clang curl sudo vim
$ curl -s https://packagecloud.io/install/repositories/cs50/repo/script.deb.sh | sudo bash
$ sudo apt-get install libcs50
$ vim test2.c # after which I added your code and saved
$ clang -lcs50 test2.c -o hello

and that indeed compiled and executed okay.

And what do you see if you execute cat /usr/include/cs50.h?

[Senya247]

@dmalan , nope I never edited the file, also, all other functions like get_int and get_float work fine and here's what I see when i do cat /usr/include/cs50.h `/**

• CS50 Library for C
• https://github.com/cs50/libcs50
• Based on Eric Roberts' genlib.c and simpio.c.
• Copyright (c) 2020
• All rights reserved
• BSD 3-Clause License
• http://www.opensource.org/licenses/BSD-3-Clause
• Redistribution and use in source and binary forms, with or without
• modification, are permitted provided that the following conditions are
• met:
• • Redistributions of source code must retain the above copyright notice,
• this list of conditions and the following disclaimer.
• • Redistributions in binary form must reproduce the above copyright
• notice, this list of conditions and the following disclaimer in the
• documentation and/or other materials provided with the distribution.
• • Neither the name of CS50 nor the names of its contributors may be used
• to endorse or promote products derived from this software without
• specific prior written permission.
• THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
• IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
• TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
• PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
• HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
• SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
• TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
• PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
• LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
• NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
• SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */

ifndef CS50_H

define CS50_H

include

include

include

include

include

/**

• Our own type for (pointers to) strings. / typedef char string;

/**

• Prompts user for a line of text from standard input and returns the
• equivalent char; if text is not a single char, user is prompted
• to retry. If line can't be read, returns CHAR_MAX. / char get_char(const char format, ...) attribute((format(printf, 1, 2)));

/**

• Prompts user for a line of text from standard input and returns the
• equivalent double as precisely as possible; if text does not represent
• a double or if value would cause underflow or overflow, user is
• prompted to retry. If line can't be read, returns DBL_MAX. / double get_double(const char format, ...) attribute((format(printf, 1, 2)));

/**

• Prompts user for a line of text from standard input and returns the
• equivalent float as precisely as possible; if text does not represent
• a float or if value would cause underflow or overflow, user is prompted
• to retry. If line can't be read, returns FLT_MAX. / float get_float(const char format, ...) attribute((format(printf, 1, 2)));

/**

• Prompts user for a line of text from standard input and returns the
• equivalent int; if text does not represent an int in [-2^31, 2^31 - 1)
• or would cause underflow or overflow, user is prompted to retry. If line
• can't be read, returns INT_MAX. / int get_int(const char format, ...) attribute((format(printf, 1, 2)));

/**

• Prompts user for a line of text from standard input and returns the
• equivalent long; if text does not represent a long in
• [-2^63, 2^63 - 1) or would cause underflow or overflow, user is
• prompted to retry. If line can't be read, returns LONG_MAX. / long get_long(const char format, ...) attribute((format(printf, 1, 2)));

/**

• Prompts user for a line of text from standard input and returns the
• equivalent long long; if text does not represent a long long in
• [-2^63, 2^63 - 1) or would cause underflow or overflow, user is
• prompted to retry. If line can't be read, returns LLONG_MAX. / long long get_long_long(const char format, ...) attribute((format(printf, 1, 2)));

/**

• Prompts user for a line of text from standard input and returns
• it as a string (char *), sans trailing line ending. Supports
• CR (\r), LF (\n), and CRLF (\r\n) as line endings. If user
• inputs only a line ending, returns "", not NULL. Returns NULL
• upon error or no input whatsoever (i.e., just EOF). Stores string
• on heap, but library's destructor frees memory on program's exit. / string get_string(va_list args, const char *format, ...) attribute((format(printf, 2, 3)));

  define get_string(...) get_string(NULL, __VA_ARGS__)

endif

`

[kzidane]

@Nightmare247 if you navigate to the folder where your source code file is and run the following commands, what is the output?

echo $0
apt-cache policy libcs50
cat ./test2.c
clang --version
clang ./test2.c -lcs50 -ohello
./hello

[jms41276]

Those warnings are what is seen when is not included. They can be promoted to errors with clang -lcs50 -test2.c -o hello -Werror. The problem recreates on my machine with that header include removed, using the original compile command. Using gdb shows that name does get set to what is typed in. Or if aborted, that get_string from libcs50.so.10 was called. Could there be a path problem, some older cs50.h is found first?

[Senya247]

@kzidane here's the output of all the commands

It still outputs weird characters.

[Senya247]

@jms41276 I thought at first that some older version was being used, so I reinstalled libcs50 with sudo apt remove libcs50 && sudo apt install libcs50, but that didn't change anything, also, here;s the output of locate cs50.h if it helps in any way

[kzidane]

Sounds like you have multiple versions of cs50.h? If you installed the library using apt (or apt-get), you should only have /usr/include/cs50.h. Did you install the one at /usr/local/include/cs50.h manually? If so, can you try removing it or moving it somewhere else temporarily and try again?

[Senya247]

@kzidane Thank you so much! I moved /usr/local/include/cs50.h somewhere else and now it finally works!