Monday, July 9, 2018

Have I Really Forgotten C?

#include
#include

int main (argc, char ** argv)
{
    float x,y;
    for (x=-2.25f; x<= 2.25f; x+=.1f)
    {
        y = pow(x, 2)-x);
        printf("%0.2f %0.2f\n", x, y);
     }
}

pow is "undefined reference to 'pow'


I needed -lm on the cc line. Thanks.
Posted by at

6 comments:

  1. CincinnatusJuly 9, 2018 at 12:06 PM

    Was the space in the include file name "math .h" in your original source? If so, that's your error.

    ReplyDelete
  2. CincinnatusJuly 9, 2018 at 12:07 PM

    Also, using quotes instead of brackets means it looks in local directory for file instead of the compiler include search path.

    ReplyDelete
  3. Paul SandJuly 9, 2018 at 12:22 PM

    Ooh, ooh, I know! (Maybe.)

    Add the '-lm' flag to your cc step to link in the math library.

    Also "#include "

    ReplyDelete
  4. smnJuly 9, 2018 at 3:53 PM

    In the text shown, the parenthesis are not balanced where y is evaluated. I see an extra ) before the semicolon at the end of the expression.

    ReplyDelete
  5. jdegeJuly 9, 2018 at 4:10 PM

    Do you have a local math.h file?

    ReplyDelete
  6. EskymanJuly 9, 2018 at 5:06 PM

    These expressions aren't allowed in The New Math. Haven't you heard?

    There's a new law coming soon, which will set Pi=3.0 That'll make everything much simpler, won't it!

    ReplyDelete

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