模拟银行叫号系统C++程序，问题描述：设银行有四个服务窗口，一个等待队列, 每个窗口均可以办理存款、取款、挂失、还贷业务，每种业务所需的服务时间不同。-Simulated bank system, called C++ programs, descr iption of the problem: Let the bank has four service windows, a queue, each window can make deposits, withdrawals, loss, loa