c++ - (C++)为什么我的程序没有输出平均等待时间和超过1小时的平均时间？

Question

这是一个使用队列模拟教师上类时间的线路的程序。它会产生随机数的学生，给他们每个在办公室花费的随机时间，然后将他们添加到队列中。还应该计算每个学生等待的平均时间，以及办公时间是否超过1个小时。
它也应该运行100次并取所有平均值。
但是，每当我运行它时，等待时间和超过1小时的时间都显示为0，我无法真正弄清楚原因。我敢肯定，这只是我忽略的一些小事情，但出于任何原因，我都无法解决。
谢谢!
让我知道您是否需要我澄清有关我的代码或问题的任何信息。
这是我的代码:

#include <iostream>
#include <ctime> //used for the time(x) function & difftime.
#include <queue>
#include <cmath>

using namespace std;

class Student{
public:
  int timeInOffice, arrivalTime, waitTime;
};

int main(){
  int numOfStudents;
  queue<Student> officeLine;
  int avgWaitFinal = 0, avgTimeInOfficeFinal = 0, avgTimeOverFinal = 0;
  //avgWaitFinal is the final average wait time
  //avgTimeinOfficeFinal is the final average time spent in office
  //avgTimeOverFinal is the average time over 1 hour spent in the office.
  for (int i=1; i <= 100; i++){
    numOfStudents = rand()%10+1;
    //This picks a random number of student between 1 and 10
    for (int j=0; j < numOfStudents; j++){
      Student st;
      st.timeInOffice = rand()%10+1;
      //this picks a random time spent in the office between 1 and 10 minutes.
      st.arrivalTime = time(0);
      officeLine.emplace(st);
    }
    int avgWait = 0, avgTimeInOffice = 0;
    time_t officeArrivalTime = time(0);
    while (! officeLine.empty()){
      Student s = officeLine.front();
      s.waitTime = time(0);
      avgWait += (int)std::round(difftime(s.waitTime, s.arrivalTime));
      avgTimeInOffice += s.timeInOffice;
      officeLine.pop();
    }
    time_t outTime = time(0);
    int totalTime = (int)std::round(difftime(outTime, officeArrivalTime));
    //this takes the difference between the time the student left and the time they arrived to calculate the total time they spent in the office.
    int timeOver = totalTime > 60 ? (totalTime - 60) : 0;
    avgTimeOverFinal += timeOver;
    avgWait = avgWait/numOfStudents;
    avgWaitFinal += avgWait;
    avgTimeInOffice = avgTimeInOffice/numOfStudents;
    avgTimeInOfficeFinal += avgTimeInOffice;
    cout<<"Run #: "<<i<<endl;
    cout<<"Number of Students: "<< numOfStudents<<endl;
    cout<<"Average Wait Time: "<<avgWait<<endl;
    cout<<"Average Visit Time: "<<avgTimeInOffice<<endl;
    cout<<"Time Over 1 Hour: "<<timeOver<<endl;
    //These are the stats for each individual run of the program
    cout<<endl;
  }
  cout<<"Overall Average Wait Time: "<< (avgWaitFinal/100)<<endl;
  cout<<"Overall Average Time in Office: "<< (avgTimeInOfficeFinal/100)<<endl;
  cout<<"Overall Average Time Over 1 Hour: "<< (avgTimeOverFinal/100)<<endl;
  //these are the final averages of 100 runs
return 0;
}

Answer 1

您可以在设置为difftime的时间变量之间多次使用time(0):它们最终会采用相同的值，因为它们几乎同时被初始化。
因此，我在其中添加了rand()术语；如果需要，可以更准确地选择这些值。
另外，在while -loop内，我将s学生项目更改为指向queue结构的指针，因此没有创建这些对象的新实例。
在您的问题下的注释中有一个有用的建议:取平均值时保留double值，然后再将其四舍五入为int。
这是我的代码修订版:

#include <iostream>
#include <ctime> //used for the time(x) function & difftime.
#include <queue>
#include <cmath>

using namespace std;

class Student{
public:
  int timeInOffice, arrivalTime, waitTime;
};

int main(){
  int numOfStudents;
  queue<Student> officeLine;
  int avgWaitFinal = 0, avgTimeInOfficeFinal = 0, avgTimeOverFinal = 0;
  //avgWaitFinal is the final average wait time
  //avgTimeinOfficeFinal is the final average time spent in office
  //avgTimeOverFinal is the average time over 1 hour spent in the office.
  for (int i=1; i <= 100; i++){
    numOfStudents = rand()%10+1;
    //This picks a random number of student between 1 and 10
    for (int j=0; j < numOfStudents; j++){
      Student st;
      st.timeInOffice = rand()%10+1;
      //this picks a random time spent in the office between 1 and 10 minutes.
      st.arrivalTime = time(0) + rand()%10+1;
      officeLine.emplace(st);
    }
    double avgWait = 0, avgTimeInOffice = 0;
    time_t officeArrivalTime = time(0);
    while ( !officeLine.empty() ){
      Student* s = &officeLine.front();
      s->waitTime = time(0);
      avgWait += difftime(s->arrivalTime, s->waitTime);
      avgTimeInOffice += s->timeInOffice;
      officeLine.pop();
    }
    time_t outTime = time(0) + rand()% 100 + 1;
    double totalTime = difftime(outTime, officeArrivalTime);
    //this takes the difference between the time the student left and the time they arrived to calculate the total time they spent in the office.
    int timeOver = totalTime > 60 ? (totalTime - 60) : 0;
    avgTimeOverFinal += timeOver;
    avgWait = std::round(avgWait/numOfStudents);
    avgWaitFinal += avgWait;
    avgTimeInOffice = std::round(avgTimeInOffice/numOfStudents);
    avgTimeInOfficeFinal += avgTimeInOffice;
    cout<<"Run #: "<<i<<endl;
    cout<<"Number of Students: "<< numOfStudents<<endl;
    cout<<"Average Wait Time: "<<avgWait<<endl;
    cout<<"Average Visit Time: "<<avgTimeInOffice<<endl;
    cout<<"Time Over 1 Hour: "<<timeOver<<endl;
    //These are the stats for each individual run of the program
    cout<<endl;
  }
  cout<<"Overall Average Wait Time: "<< (avgWaitFinal/100)<<endl;
  cout<<"Overall Average Time in Office: "<< (avgTimeInOfficeFinal/100)<<endl;
  cout<<"Overall Average Time Over 1 Hour: "<< (avgTimeOverFinal/100)<<endl;
  //these are the final averages of 100 runs
return 0;
}