foo.cc: In function 'int main()':
foo.cc:9:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |  for(int i=0;i<a.length();i++){
      |              ~^~~~~~~~~~~
foo.cc:23:29: error: expected primary-expression before '<' token
   23 |  cout<<c<<endl<<b<<endl<<d<<<endl<e;
      |                             ^
foo.cc:23:35: error: the value of 'e' is not usable in a constant expression
   23 |  cout<<c<<endl<<b<<endl<<d<<<endl<e;
      |                                   ^
foo.cc:7:18: note: 'int e' is not const
    7 |  int b=0,c=0,d=0,e=0;
      |                  ^
foo.cc:23:30: error: parse error in template argument list
   23 |  cout<<c<<endl<<b<<endl<<d<<<endl<e;
      |                              ^~~~~~

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