/in/foo.cc: In function 'int main(int, const char**)':
/in/foo.cc:9:11: 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/c++/5/ext/string_conversions.h:43,
                 from /usr/include/c++/5/bits/basic_string.h:5249,
                 from /usr/include/c++/5/string:52,
                 from /usr/include/c++/5/bits/locale_classes.h:40,
                 from /usr/include/c++/5/bits/ios_base.h:41,
                 from /usr/include/c++/5/ios:42,
                 from /usr/include/c++/5/ostream:38,
                 from /usr/include/c++/5/iostream:39,
                 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:9:11: 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/c++/5/ext/string_conversions.h:43,
                 from /usr/include/c++/5/bits/basic_string.h:5249,
                 from /usr/include/c++/5/string:52,
                 from /usr/include/c++/5/bits/locale_classes.h:40,
                 from /usr/include/c++/5/bits/ios_base.h:41,
                 from /usr/include/c++/5/ios:42,
                 from /usr/include/c++/5/ostream:38,
                 from /usr/include/c++/5/iostream:39,
                 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:9:17: 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/c++/5/ext/string_conversions.h:43,
                 from /usr/include/c++/5/bits/basic_string.h:5249,
                 from /usr/include/c++/5/string:52,
                 from /usr/include/c++/5/bits/locale_classes.h:40,
                 from /usr/include/c++/5/bits/ios_base.h:41,
                 from /usr/include/c++/5/ios:42,
                 from /usr/include/c++/5/ostream:38,
                 from /usr/include/c++/5/iostream:39,
                 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:11:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<strlen(a);i++)
                      ^
/tmp/ccm4nVrP.o: In function `main':
foo.cc:(.text.startup+0x6c): warning: the `gets' function is dangerous and should not be used.