/in/foo.c: In function 'main':
/in/foo.c:11:2: 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:12:2: 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:13:12: warning: passing argument 1 of 'length' from incompatible pointer type [-Wincompatible-pointer-types]
  x1=length(s1);
            ^~
/in/foo.c:4:5: note: expected 'int *' but argument is of type 'char *'
 int length(int s[ ]);
     ^~~~~~
/in/foo.c:15:12: warning: passing argument 1 of 'length' from incompatible pointer type [-Wincompatible-pointer-types]
  x2=length(s2);
            ^~
/in/foo.c:4:5: note: expected 'int *' but argument is of type 'char *'
 int length(int s[ ]);
     ^~~~~~
/in/foo.c: In function 'length':
/in/foo.c:25:15: warning: passing argument 1 of 'strlen' from incompatible pointer type [-Wincompatible-pointer-types]
  count=strlen(s);
               ^
In file included from /in/foo.c:2:0:
/usr/include/string.h:394:15: note: expected 'const char *' but argument is of type 'int *'
 extern size_t strlen (const char *__s)
               ^~~~~~
/tmp/ccUgMpyv.o: In function `main':
foo.c:(.text.startup+0x18): warning: the `gets' function is dangerous and should not be used.