usedatabase2.cpp

C语言数值算法程序大全（第二版）,课本文件

//: C09:UseDatabase2.cpp
// From "Thinking in C++, 2nd Edition, Volume 2"
// by Bruce Eckel & Chuck Allison, (c) 2003 MindView, Inc.
// Available at www.BruceEckel.com.
// Tests the Countable "mixin" class
#include <cassert>
#include "DBConnection.h"

class DBClient {
public:
  DBClient(DBConnection* dbCon) {
    db = dbCon;
    db->attach();
  }
  ~DBClient() {
    db->detach();
  }
  // Other database requests using db...
private:
  DBConnection* db;
};

int main() {
  DBConnection* db = DBConnection::create("MyDatabase");
  assert(db->refCount() == 1);
  DBClient c1(db);
  assert(db->refCount() == 2);
  DBClient c2(db);
  assert(db->refCount() == 3);
  // Use database, then release attach from original create
  db->detach();
  assert(db->refCount() == 2);
} ///:~