《Cracking the Coding Interview》——第8章：面向对象设计——题目2

2014-04-23 17:45

题目：假设有个呼叫中心，有接线员、经理、主管三种角色。如果接线员无法处理呼叫，就上传给经理；如果仍无法处理，则上传给主管。请用代码描述这一过程。

解法：第一眼觉得这题肯定是在考察设计模式，很像exception的throw过程。对于我这种对设计模式一窍不通的人，这题还无法很好解答。待稍后专门学习设计模式之后，再回来好好琢磨一遍。

代码：

 // 8.2 Design a call center system to handle calls, the order will be respondent->manager->director, find the first employee to handle a call.
 #include <iostream>
 #include <vector>
 using namespace std;

 class People {
 public:
     People() {};
     virtual void handle() = ;
     virtual ~People() {};
 };

 class Respondent: public People {
 public:
     Respondent() {};
     void handle() {
         cout << "Respondent is handling the call." << endl;
     };
     ~Respondent() {};
 };

 class Manager: public People {
 public:
     Manager() {};
     void handle() {
         cout << "Manager is handling the call." << endl;
     };
     ~Manager() {};
 };

 class Director: public People {
 public:
     Director() {};
     void handle() {
         cout << "Director is handling the call." << endl;
     };
     ~Director() {};
 };

 class CallCenter {
 public:
     CallCenter(int num_respondent = , int num_manager = , int num_director = ) {
         respondents.resize(num_respondent);
         managers.resize(num_manager);
         directors.resize(num_director);
         respondents_available.resize(num_respondent);
         managers_available.resize(num_manager);
         directors_available.resize(num_director);
         fill(respondents_available.begin(), respondents_available.end(), true);
         fill(managers_available.begin(), managers_available.end(), true);
         fill(directors_available.begin(), directors_available.end(), true);
     }

     void handle() {
         size_t i;

         for (i = ; i < respondents.size(); ++i) {
             if (respondents_available[i]) {
                 break;
             }
         }
         if (i < respondents.size()) {
             respondents_available[i] = false;
             respondents[i].handle();
             respondents_available[i] = true;
             return;
         }

         for (i = ; i < managers.size(); ++i) {
             if (managers_available[i]) {
                 break;
             }
         }
         if (i < managers.size()) {
             managers_available[i] = false;
             managers[i].handle();
             managers_available[i] = true;
             return;
         }

         for (i = ; i < directors.size(); ++i) {
             if (directors_available[i]) {
                 break;
             }
         }
         if (i < directors.size()) {
             directors_available[i] = false;
             directors[i].handle();
             directors_available[i] = true;
             return;
         }
     }
 private:
     vector<Respondent> respondents;
     vector<Manager> managers;
     vector<Director> directors;
     vector<bool> respondents_available;
     vector<bool> managers_available;
     vector<bool> directors_available;
 };

 int main()
 {
     CallCenter *p_call_center = nullptr;
     int r, m, d;

     while (cin >> r >> m >> d) {
         p_call_center = new CallCenter(r, m, d);
         p_call_center->handle();
         delete p_call_center;
         p_call_center = nullptr;
     }

     return ;
 }