text: #include <unistd.h>
  #include <cstddef>
  #include <set>
  #include <string>
  #include <vector>
  
  #include "process.h"
  #include "processor.h"
  #include "system.h"
  #include "linux_parser.h"
  
  using std::set;
  using std::size_t;
  using std::string;
  using std::vector;
  
    //Accessors
     // DONE: Return the system's CPU
    Processor& System::Cpu() { 
      return cpu_; 
      
      }
  
    // DONE: Return a container composed of the system's processes
    vector<Process>& System::Processes() {  
      System::UpdateProcesses();
      return processes_; 
    }
  
    // DONE: Return the system's kernel identifier (string)
    std::string System::Kernel() { 
      return kernel_; 
    }
  
    // DONE: Return the system's memory utilization
    float System::MemoryUtilization() { 
      return LinuxParser::MemoryUtilization();
    }
  
    // DONE: Return the operating system name
    std::string System::OperatingSystem() { 
      return operatingsystem_ ;
    }
  
    // DONE: Return the number of processes actively running on the system
    int System::RunningProcesses() {
      return LinuxParser::RunningProcesses();
      }
  
    // DONE: Return the total number of processes on the system
    int System::TotalProcesses() { 
      return LinuxParser::TotalProcesses() ;
    }
  
    // DONE: Return the number of seconds since the system started running
  
    long int System::UpTime() { 
      return LinuxParser::UpTime();
    }
  
  