Making a Class Writable to a Stream - C++ Class

C++ examples for Class:Operator Overload

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Description

Making a Class Writable to a Stream

Demo Code

#include <iostream>
#include <string>

using namespace std;

class Employer {/*from w w  w. ja va  2 s .c  o m*/
   friend ostream& operator<<              // This has to be a friend
     (ostream& out, const Employer& empr); // so it can access non-
public:                                    // public members
   Employer() {}
  ~Employer() {}

   void setName(const string& name) {name_ = name;}
private:
   string name_;
};

class Employee {
   friend ostream& operator<<
     (ostream& out, const Employee& obj);
public:
   Employee() : empr_(NULL) {}
  ~Employee() {if (empr_) delete empr_;}

   void setFirstName(const string& name) {firstName_ = name;}
   void setLastName(const string& name) {lastName_ = name;}
   void setEmployer(Employer& empr) {empr_ = &empr;}
   const Employer* getEmployer() const {return(empr_);}

private:
   string firstName_;
   string lastName_;
   Employer* empr_;

};

// Allow us to send Employer objects to an ostream...
ostream& operator<<(ostream& out, const Employer& empr) {

   out << empr.name_ << endl;

   return(out);
}

// Allow us to send Employee objects to an ostream...
ostream& operator<<(ostream& out, const Employee& emp) {
   out << emp.firstName_ << endl;
   out << emp.lastName_ << endl;
   if (emp.empr_)
     out << *emp.empr_ << endl;

   return(out);
}

int main() {

   Employee emp;
   string first = "first";
   string last = "last";
   Employer empr;
   string name = "abc";
   empr.setName(name);

   emp.setFirstName(first);
   emp.setLastName(last);
   emp.setEmployer(empr);

   cout << emp;  // Write to the stream
}

Result


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