4.11-2.cpp

#include <string>

extern char ch;
extern std::string s;
extern int count;
extern const double pi;
int error_number = 1;
extern const char* name;
extern const char* season[];
struct Date;
int day(Date*);
double sqrt(double d) { return d; }
template <class T> T abs (T a);
typedef std::string Stroka;
struct User { int a; };

namespace NS{};

int main() {
    return 0;
}