error: expected unqualified-id before ‘const’

Question

I have seen a few questions on this error, but I don't have much experience with making a class in C++, so I don't actually understand what the answers mean. I should also point out that I didn't write this code.

I'm getting the error stated in the title, and I believe it's coming from this header file, but I have no idea what the error means and how to fix it.

Here is the file:

#ifndef _QUICKTIMER_H_
#define _QUICKTIMER_H_

#include <cstdlib>
#include <string>
#include <chrono>

class QuickTimer {
public:
  QuickTimer(const std::string& prefix = "");
  ~QuickTimer();
private:
  std::chrono::high_resolution_clock::time_point mStartTime;
  const std::string mPrefix;
};

#endif

and the full errors:

error: expected unqualified-id before ‘const’
 QuickTimer(const std::string& prefix) :
            ^  

error: expected ‘)’ before ‘const’

error: declaration of ‘~QuickTimer’ as non-member
 ~QuickTimer()
             ^

If anyone could explain to me what it means and what's going on, I'd really appreciate it, thanks!

Answer 1

Class name prefix are probably missing in the definition of your constructor and destructor. You should have something like that in a cpp file :

QuickTimer::QuickTimer(const std::string& prefix)
{
}

QuickTimer::~QuickTimer()
{
}