模拟银行家算法，检测死锁。当用户申请一组资源时，系统必须确定这些资源的分配是否仍会使系统处于安全状态。如果会，就可分配资源；否则，进程必须等待直到某个其他进程释放足够资源为止。-It is on simulating banker arithmetic and detecting death lock. When user applies a group of resource, the system must decide if assigning the source still keep itself in safe state. If the system be still in safe state, it will assign,otherwise, it will not assign.