/in/foo.c: In function 'Length':
/in/foo.c:5:7: warning: unused variable 'c' [-Wunused-variable]
  char c;
       ^
/in/foo.c: In function 'main':
/in/foo.c:15:4: warning: 'gets' is deprecated [-Wdeprecated-declarations]
    gets(s1);
    ^~~~
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:16:4: warning: 'gets' is deprecated [-Wdeprecated-declarations]
    gets(s2);
    ^~~~
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: In function 'Length':
/in/foo.c:6:8: warning: 'n' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int i,n,len;
        ^
/in/foo.c: In function 'main':
/in/foo.c:6:8: warning: 'n' may be used uninitialized in this function [-Wmaybe-uninitialized]
/in/foo.c:6:8: warning: 'n' may be used uninitialized in this function [-Wmaybe-uninitialized]
/tmp/ccaz1G6S.o: In function `main':
foo.c:(.text.startup+0x18): warning: the `gets' function is dangerous and should not be used.