CODEWITHSUNDEEP
c++swap
Li Yang
Li Yang

Reputation: 5

cannot swap objects in an array in C++

i am new to C++ and stuck in the swap stuff the code below is a program of sort employee names in alphbetical order and print out the orginal one and sorted one ,but the swap method doesn't work the two output of printEmployees is excatly the same, can anyone help me? thx

    #include <iostream>

    #include <string>

    #include <iomanip>

    #include <algorithm>
using namespace std;


class employee
{

   /* Employee class to contain employee data
   */

   private:
     string surname;
     double hourlyRate;
     int empNumber; 
   public:
      employee() {
         hourlyRate = -1;
         empNumber = -1;
         surname = "";
      }
      employee(const employee &other) :
         surname(other.surname),
         hourlyRate(other.hourlyRate),
         empNumber(other.empNumber){}

      void setEmployee(const string &name, double rate,int num);
      string getSurname() const;
      void printEmployee() const;
     employee& operator = (const employee &other)
    {employee temp(other);
     return *this;}};    

     void employee::setEmployee(const string &name, double rate, int num) {   
      surname = name;
      hourlyRate = rate;
      empNumber = num;
      }
     string employee::getSurname() const { return surname; }  
     void employee::printEmployee() const {
         cout << fixed;
         cout << setw(20) << surname << setw(4) << empNumber << "  " << hourlyRate << "\n";
      }

  void printEmployees(employee employees[], int number)
   {
   int i;
    for (i=0; i<number; i++) { employees[i].printEmployee();   }
   cout << "\n";
   }


void swap(employee employees[], int a, int b)
{
  employee temp(employees[a]);
employees[a] = employees[b];
employees[b] = temp;

}


void sortEmployees(employee employees[], int number)
{
   /* use selection sort to order employees, 
      in employee 

name order
   */


    int inner, outer, max;


    for (outer=number-1; outer>0; outer--)
   {
      // run though array number of times
      max = 0;
      for (inner=1; 

inner<=outer; inner++)
      {
         // find alphabeticaly largest surname in section of array
         if (employees

[inner].getSurname() < employees[max].getSurname())
            max = inner;
      }
      if (max != outer)
      {
         // 

swap largest with last element looked at in array
         swap(employees, max, outer);
      }
   }
}


int main()
{
   employee employees[5];

   employees[0].setEmployee("Stone", 35.75, 053);
   employees[1].setEmployee

("Rubble", 12, 163);
   employees[2].setEmployee("Flintstone", 15.75, 97);
   employees[3].setEmployee("Pebble", 10.25, 104);


  employees[4].setEmployee("Rockwall", 22.75, 15);


   printEmployees(employees, 5);

   sortEmployees(employees,5);
   printEmployees(employees, 5);

   return 0;
}

Upvotes: 0

Views: 2624

Answers (2)

Jagannath
Jagannath

Reputation: 4025

As told by others, fixing your assignment operator will solve the problem.
I see that you tried to implement operator= in terms of copy constructor but missed to do a swap. You can try the below approach if you want to avoid code duplication in your copy constructor and assignment operator. 

employee& operator=(const employee& other)
{
    employee temp(other);
    swap(temp);
    return *this;
}

void swap(employee& other)
{
     std::swap(surname, other.surname);
     std::swap(hourlyRate, other.hourlyRate);
     std::swap(empNumber, other.empNumber);
}

Upvotes: 0

David Schwartz
David Schwartz

Reputation: 182753

This code is broken:

 employee& operator = (const employee &other)
{employee temp(other);
 return *this;}

It should be something like:

employee& operator= (const employee &other)
{
   surname = other.surname;
   hourlyRate = other.hourlyRate;
   empNumber = other.empNumber;
   return *this;
}

Upvotes: 3

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