/in/foo.c: In function 'main':
/in/foo.c:7:2: 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:7:7: warning: passing argument 1 of 'gets' from incompatible pointer type [-Wincompatible-pointer-types]
  gets(s1);
       ^~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: expected 'char *' but argument is of type 'int *'
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c:8:2: 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:8:7: warning: passing argument 1 of 'gets' from incompatible pointer type [-Wincompatible-pointer-types]
  gets(s2);
       ^~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: expected 'char *' but argument is of type 'int *'
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c:10:14: warning: passing argument 1 of 'strlen' from incompatible pointer type [-Wincompatible-pointer-types]
  len1=strlen(s1);
              ^~
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)
               ^~~~~~
/in/foo.c:11:14: warning: passing argument 1 of 'strlen' from incompatible pointer type [-Wincompatible-pointer-types]
  len2=strlen(s2);
              ^~
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/cccIXF4r.o: In function `main':
foo.c:(.text.startup+0x18): warning: the `gets' function is dangerous and should not be used.