I've created a new workspace on cloud9, and ran update50 as suggested in the answer to this similar question: Undefined reference to get_int

However, I still receive the exception 'undefined reference to `get_int'' in my terminal with this code that was copied/pasted from Week 1's notes.

#include <cs50.h>
#include <stdio.h>

int main(void)
    int i = get_int("Integer: ");
    printf("hello, %i\n", i);

I've tried a few other things like resetting the workspace to default and executing update50 again, but the problem persists.


On which version of the workspace are you? The current version as of 2017-11-13 is v125. If update50 doesn't end in an error message, you probably are at that version.

Also, how do you compile? The default of

make hello

would use environment variable LDLIBS with content -lcrypt -lcs50 -lm. Here the -lcs50 is relevant, it tells the linker (which is invoked by the compiler) to link against library cs50.

The minimal compile command line would be

clang hello.c -o hello -lcs50

but better use make (which takes the target, not its source, so run make hello, not make hello.c).

  • Hi, using make hello worked fine. I tried clang hello.c, which worked fine for the Hello World example but failed for the Get Integer one, now I know why...thanks for the help. – JohnWick Nov 14 '17 at 0:20

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