Shuttle Bus

1. Derived from the shuttle bus schedule announced by NCNU, we have a plain-text version which can be handled easier in C++. In each line, the three fields represent the weekday, the destination, and the departure time. For example, "0 Puli 12:10" means there will be a shuttle bus bound for Puli at 12:10 on Sunday.
2. If you want to download a file into your directory on STU, you may type the command "wget http://ipv6.ncnu.org/Course/C_Programming.1022/C/shuttle.txt".
3. Alternatively, you may simply retrieve a common file which we stored at a public directory "/home/cs2015", as shown in the following example.
4. To read the contents from a file, you will need the fopen, fscanf, fclose() functions.

   
   int main()
   {
       int d;
       char destination[5];
       char departure_time[6];
       FILE* fp = fopen("/home/cs2015/shuttle.txt", "r");
       while( fscanf(fp, "%d %s %s", &d, destination, departure_time) != EOF )
       {
           cout << d << destination << departure_time << endl;
       }
       fclose(fp);
   }
   
   

5. Moreover, we want the program to be more flexible, so that in addition to allow a user to query the shuttle bus departure time based on current time, the user can also specify a time, or even a weekday on the command line. For example, "shuttle 14:00 6" tries to look up the next shuttle bus around 14:00 on Saturday.
6. To get arguments from the command line, as we did in Python, we may inspect the arguments passed from the operating system to our main function. Suppose you have a program:

   
   #include <iostream>
   #include <ctime>
   using std::cout;
   using std::endl;
   
   int main(int argc, char* argv[])
   {
       char now[] = "00:00";
       time_t rawtime;
       time( &rawtime );
       struct tm *timeinfo = localtime( &rawtime );
       strftime(now, 5, "%H:%M", timeinfo);
   
       if (argc == 2)
           strcpy(now, argv[1]);
   
       cout << "Now is " << now << endl;
       return 0;
   }
   
   

   When you run "argv.exe", you get the current time.
   When you run "argv.exe 18:00", we get "Now is 18:00".

• shuttle.exe

  
  Now is 17:44
  The shuttle bus leaves for Puli at 18:10
  The shuttle bus leaves for NCNU at 18:10
  
  

• shuttle.exe 07:00

  
  At 07:00, you may consider:
  The shuttle bus leaves for Puli at 08:10
  The shuttle bus leaves for NCNU at 07:30
  
  

• shuttle.exe 14:00 6

  
  At 14:00, you may consider:
  The shuttle bus leaves for Puli at 15:10
  The shuttle bus leaves for NCNU at 15:40
  
  

• shuttle.exe 14:00 0

  
  At 14:00, you may consider:
  The shuttle bus leaves for Puli at 14:10
  The shuttle bus leaves for NCNU at 14:40
  
  

• shuttle.exe 23:00 0

  
  At 23:00, you may consider:
  The last shuttle bus bound for Puli has left.
  The last shuttle bus bound for NCNU has left.