0001 template <typename T> struct CheckOrder { //函数对象：判断一个T类对象是否局部有序
0002    T pred; int& u;
0003    CheckOrder( int& unsorted, T& first ) : pred( first ), u( unsorted ) {}
0004    virtual void operator()( T& e ) { if ( pred > e ) u++; pred = e; }
0005 };