/in/ex3.c: In function 'str2num':
/in/ex3.c:43:23: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
     for (int i = 0; i < strlen(str); i++)
                       ^
/in/ex3.c: In function 'main':
/in/ex3.c:112:15: error: suggest parentheses around comparison in operand of '&' [-Werror=parentheses]
         if (i & 2 == 0)
               ^
/in/ex3.c: In function 'str2num':
/in/ex3.c:42:9: error: 'num' may be used uninitialized in this function [-Werror=maybe-uninitialized]
     int num;
         ^~~
/in/ex3.c: In function 'bfs':
/in/ex3.c:57:25: error: 'space' may be used uninitialized in this function [-Werror=maybe-uninitialized]
     changestr[spacenum] = changestr[changenum];
     ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/in/ex3.c:66:9: note: 'space' was declared here
     int space;
         ^~~~~
cc1: all warnings being treated as errors