/in/foo.cc: In function 'int main()':
/in/foo.cc:6:11: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
     while(gets(a))
           ^
In file included from /usr/include/c++/5/cstdio:42:0,
                 from /usr/include/x86_64-linux-gnu/c++/5/bits/stdc++.h:46,
                 from /in/foo.cc:1:
/usr/include/stdio.h:638:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^
/in/foo.cc:6:11: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
     while(gets(a))
           ^
In file included from /usr/include/c++/5/cstdio:42:0,
                 from /usr/include/x86_64-linux-gnu/c++/5/bits/stdc++.h:46,
                 from /in/foo.cc:1:
/usr/include/stdio.h:638:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^
/in/foo.cc:6:17: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
     while(gets(a))
                 ^
In file included from /usr/include/c++/5/cstdio:42:0,
                 from /usr/include/x86_64-linux-gnu/c++/5/bits/stdc++.h:46,
                 from /in/foo.cc:1:
/usr/include/stdio.h:638:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^
/in/foo.cc:8:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<strlen(a);i++)
                      ^
/tmp/cc8BbQe6.o: In function `main':
foo.cc:(.text.startup+0x29): warning: the `gets' function is dangerous and should not be used.