text: #ifndef SYSTEM_H
  #define SYSTEM_H
  
  #include <string>
  #include <vector>
  
  #include "process.h"
  #include "processor.h"
  
  class System {
    public:
      System();
      Processor& Cpu();                   // TODO: See src/system.cpp
      std::vector<Process>& Processes();  // TODO: See src/system.cpp
      float MemoryUtilization();          // TODO: See src/system.cpp
      long UpTime();                      // TODO: See src/system.cpp
      int TotalProcesses();               // TODO: See src/system.cpp
      int RunningProcesses();             // TODO: See src/system.cpp
      std::string Kernel();               // TODO: See src/system.cpp
      std::string OperatingSystem();      // TODO: See src/system.cpp
  
    // TODO: Define any necessary private members
    private:
      long startTime_ = 0;
      long cachedUpTime_;
      Processor cpu_;
      std::vector<Process> processes_ = {};
  };
  
  #endif