/in/foo.c: In function 'main':
/in/foo.c:14:6: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
   if (a[0] != 0)
      ^
/in/foo.c:37:6: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
   if (a[n-1] != 0)
      ^
/in/foo.c:44:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   if (a[n] != 0);
   ^~
/in/foo.c:45:4: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
    printf("+%d\n", a[n]);
    ^~~~~~