/in/foo.c: In function 'main':
/in/foo.c:7:2: warning: 'gets' is deprecated [-Wdeprecated-declarations]
  gets(a);
  ^~~~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c:10:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(i=0;i<len;i++)
  ^~~
/in/foo.c:13:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   printf("\n");
   ^~~~~~
/tmp/ccKkiWqU.o: In function `main':
foo.c:(.text.startup+0x12): warning: the `gets' function is dangerous and should not be used.