/in/foo.c: In function 'main':
/in/foo.c:5:2: warning: 'gets' is deprecated [-Wdeprecated-declarations]
  gets(s1);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:5:2: warning: 'gets' is deprecated [-Wdeprecated-declarations]
  gets(s1);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:15:8: warning: iteration 26 invokes undefined behavior [-Waggressive-loop-optimizations]
   if(s1[i]>=97&&s1[i]<=122)
      ~~^~~
/in/foo.c:7:2: note: within this loop
  for(i=0;i<100005;i++)
  ^~~
/tmp/ccAH3W4m.o: In function `main':
foo.c:(.text.startup+0x15): warning: the `gets' function is dangerous and should not be used.