foo.cc: In function 'int main()':
foo.cc:41:8: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
  gets(s);
        ^
In file included from /usr/include/stdio.h:862:0,
                 from /usr/include/c++/7/cstdio:42,
                 from /usr/include/c++/7/ext/string_conversions.h:43,
                 from /usr/include/c++/7/bits/basic_string.h:6361,
                 from /usr/include/c++/7/string:52,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:232:1: note: declared here
 gets (char *__str)
 ^~~~
foo.cc:42:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0;i < strlen(s);i++)
                 ~~^~~~~~~~~~~
foo.cc:47:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0;i < strlen(s)-1;)
                 ~~^~~~~~~~~~~~~
foo.cc:41:6: warning: ignoring return value of 'char* gets(char*)', declared with attribute warn_unused_result [-Wunused-result]
  gets(s);
  ~~~~^~~
/tmp/ccHkrTqy.o: In function `main':
foo.cc:(.text.startup+0x67): warning: the `gets' function is dangerous and should not be used.

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