/in/foo.c: In function 'main':
/in/foo.c:7:2: warning: 'gets' is deprecated [-Wdeprecated-declarations]
  gets(s);
  ^~~~
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:17:9: warning: iteration 99 invokes undefined behavior [-Waggressive-loop-optimizations]
   a[i+1]+=a[i]/10;
         ^~
/in/foo.c:15:2: note: within this loop
  for(i=0;i<100;i++)
  ^~~
/tmp/cci7I46A.o: In function `main':
foo.c:(.text.startup+0x3a): warning: the `gets' function is dangerous and should not be used.