When I run breakout these error happen:

breakout.c:141:9: error: unused variable 'row_space'
    int row_space = 20;


breakout.c:29:11: error: implicit declaration of function
      'time' is invalid in C99

Maybe I am just looking way to hard to find these errors


Code removed per Honor Code

  • Please make sure to mark an answer as accepted if it solved your issue. :) Commented Jul 28, 2015 at 9:21

1 Answer 1

  1. First error is caused by, as the message says, declaration of a variable that's never used. If you're wondering how that's an error, I suggest you to watch this CS50 short short on how clang and in turn make work: Make, Clang.

    In short (no pun intended), since CS50 staff decided you are supposed to run programs with absolutely no errors whatsoever, they made make (which isn't compiler itself) invoke clang (that's the one!) with -Werror and -Wall options. It turns on all warnings (like the unused variable one) and makes them errors, thus stopping your program from being compiled.

    Edit: Seems like I got carried on and haven't explained enough what is actually causing an error.

    You declared variable, row_space, in line 141 of your program, with value 20. Your mistake, and thus error, is that you're not using it throughout your program, i.e. you're changing its value, use any functions with it as argument, etc. Its existence in your code is bassically pointless and compiler is pointing that out.

  2. You used time() function, which isn't in any of the libraries you supplied. Try to use man command or reference page to find the correct one.

  • Virzen, thanks for the help. But when I do Clang -Wall it says error: no input files
    – Ani
    Commented Jul 29, 2015 at 13:59
  • Well, my point wasn't to make you use clang directly, but to draw your attention to the fact, that you declared variable row_space and never used it. Commented Jul 29, 2015 at 20:47
  • I have edited my answer with more details. Commented Jul 29, 2015 at 20:56
  • Thanks! I have removed a useless variable. But that leads to a MAJOR problem. Link here: cs50.stackexchange.com/questions/10866/…
    – Ani
    Commented Jul 30, 2015 at 13:39

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