I am getting the error in xcode Undefined symbols for architecture x86_64: “InputStream::Set()”, referenced from: Average(InputStream&) in Average2-12ad49.o “InputStream::Get() const”, referenced from: Average(InputStream&) in Average2-12ad49.o ld: symbol(s) not found for architecture x86_64 Is this somehow related to g++’s version?

Average2.cpp

#include "InputStream.h" #include <iostream>  using namespace std;  bool Average(InputStream& stream) {   int count;   double avr = 0;   for(count = 0; stream.Set(); ++count) {     avr += stream.Get();  }  if(count == 0) {     return false;  }   avr /= count;  cout << "The average is " << avr << endl;  return true; }  int main() {  while(true) {     InputStream stream;     if(! Average(stream)) {         break;     }   } } 

InputStream.h

#ifndef INPUTSTREAM_H_ #define INPUTSTREAM_H_  class InputStream { public:  double Get() const;  bool Set();  private:  double m_n; };  #endif 

InputStream.cpp

#include "InputStream.h" #include <iostream> using namespace std;  double Inputstream::Get() const {   return m_n; }  bool InputStream::Set() {  cin >> m_n;  return m_n >= 0; }