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#include <string> class Connection { public: void* execute(std::string query) { return nullptr; } void commit() { } void close() { } }; class Transaction { private: Connection* conn; public: Transaction(Connection* conn) : conn(conn) {} void* execute(std::string query) { return conn->execute(query); } void commit() { conn->commit(); } void rollback() { } }; Connection* getConnection() { static Connection conn; return &conn; }