implementing operators

i need guidance here please. i need to implement the +, = , == operators on my savingsaccount class. i really dont know where to start and any guidance will really be appreciated. here are my codes:

//SavingsAccount.h
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Code:

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#ifndef SAVINGSACCOUNT_H
#define SAVINGSACCOUNT_H

class SavingsAccount
{
    public:
        SavingsAccount(double x)
  {
        savingsBalance = x >= 0 ? x:0;
  }
    void calculateMonthlyInterest();
    static void modifyInterestRate(double);
    void printoutBalance() const;

    private:
        double savingsBalance;
        static double annualInterestRate;

};

---

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//SavingsAccount.cpp
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Code:

---

#include <iostream>
#include <iomanip>
#include "SavingsAccount.h"

double SavingsAccount::annualInterestRate = 0;

void SavingsAccount::calculateMonthlyInterest()
{
    savingsBalance += savingsBa lance * (annualInterestRate / 2.0);
}
 
void SavingsAccount::modifyInterestRate(double y)
{
    annualInterestRate = (y >= 0  && y <= 1.0) ? y:0.03;
}

void SavingsAccount::printoutBalance() const
{
    std::cout << '$' << savingsBalance << std::endl;
}

---

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//main.cpp
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Code:

---

#include <iostream>
#include <iomanip>
#include "SavingsAccount.h"

int main()
{
    SavingsAccount saver1(2000.0), saver2(3000.0);

    SavingsAccount::modifyInterestRate(.03);

    std::cout << "Monthly balances with 3% annual interest"
                    << \ntBalances:\n\t\t\tSaver 1=>";
    saver1.printoutBalance();

    std::cout << "Saver 2=>";
    saver2.printoutBalance();

    for (int m = 1; m <= 12; ++m)
  {
        saver1.calculateMonthlyInterest();
        saver2.calculateMonthlyInterest();

        std::cout <<"\nMonth " << m << ":Saver 1=>";
        saver1.printoutBalance();
        std::cout << "Saver 2=>";
        saver2.printoutBalance();
    }

    SavingsAccount::modifyInterestRate(.04);
    saver1.calculateMonthlyInterest();
    saver2.calculateMonthlyInterest();
    std::cout << "\nBalances with 4% interest rate:"
                    << "\nBalances:\nSaver 1=>";
    saver1.printoutBalance();
    std::cout << "Saver 2=>";
    saver2.printoutBalance();
    std::cout << std::endl;

    return 0;
}

---

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thankyou very much in advance!!

first I think you should at a public accesser function to return savingsBalance. then you can do something like:

Code:

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void SavingsAccount::operator+ (SavingsAccount blah){
    return (savingsBalance+blah.getSavingsBalance() );
}

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thats if you make it a member function, I'm sure some people will insist on overloaded operators to be non member or something. but you get the idea...

Quote:

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Originally Posted by qwertiop

first I think you should at a public accesser function to return savingsBalance. then you can do something like:

Code:

---

void SavingsAccount::operator+ (SavingsAccount blah){
    return (savingsBalance+blah.getSavingsBalance() );
}

---

thats if you make it a member function, I'm sure some people will insist on overloaded operators to be non member or something. but you get the idea...

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this is Bad...
look at the string class to see how its done ...
it should be like this :

Code:

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//file: SavingsAccount.h
class SavingAccount
{
  //...
  SavingAccount operator + (SavingAccount& rAcc);
  bool operator ==  (const SavingAccount& rAcc);
  SavingAccount& operator = (const SavingAccount& rAcc);
  //...
};
///:~

//file:  SavingsAccount.cpp
//...
SavingAccount SavingAccount::operator + (SavingAccount& rAcc)
{
  SavingAccount acc;
  //..do some stuff with (*this)
  //and return the result in acc so that the people could write:
  //
  // a1 = a2 + a3 + a4;
  //

  acc.savingsBalance = this->savingsBalance + rAcc.savingsBalance;
  return acc;
}
bool SavingAccount::operator ==  (const SavingAccount& rAcc)
{
  bool bret = false;
  //do some stuff here
  bret = this->savingsBalance == rAcc.savingsBalance;
  return bret;
}
SavingAccount& SavingAccount::operator = (const SavingAccount& rAcc)
{
  //do some stuff for assignment
  this->savingsBalance = rAcc.savingsBalance;
  return *this;
}
//...

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