Question

Create the class savings account. Use the static variable annualInterestRate to store the annual interest rate for all account holders. Each object of the classcontains a private instance variable savingsBalance, indicating the amount the saver currently has on deposit. Provide method CalculateMonthlyInterest to calculate themonthly interest by multiplying the savingsBalance by annualInterestRate divided by 12, this interest should be added to savingsBlance, Provide static methodModifyInterestRate to set the annualInterestRate to a new value. Write an application to test class SavingsAccount. Create two savings Account objects, saver1 andsaver2, with balances of $2000 and 3000. Set annualInterestRate to 4%, then calculate the monthly interest and display the new balances for both savers. Then set theannualInterestRate to 5%, calculate the next months interest and display the new balances for both savers.

Answer 1

#include <iostream>

using namespace std;

class SavingsAccount
{
public:
SavingsAccount(){}
SavingsAccount(int value);
~SavingsAccount(){}
static float annualInterestRate;
void calculateMonthlyInterest();
static void modifyIntererestRate(float value);
float GetBalance() const { return savingsBalance; }
private:
// Each member of the class contains a private data member
// savingsBalance indicating the amount the saver currently has
// on deposit.
float savingsBalance;
};

// copy constructor to initialize the value at instantiation
SavingsAccount::SavingsAccount(int value)
{
savingsBalance = value;
}

// Use a static data member annualInterestRate to store the annual interest
// rate for each of the savers.
float SavingsAccount::annualInterestRate = 0;

// Provide member function calculateMonthlyInterest that calculates the
// monthly interest by multiplying the savingsBalance by annualInterestRate
// divided by 12 and then adds this interest to savingsBalance.
void SavingsAccount::calculateMonthlyInterest()
{
savingsBalance += ((savingsBalance * annualInterestRate) / 12);
}

//Provide a static member function modifyIntererestRate that sets the
// static annualInterestRate to a new value.
void SavingsAccount::modifyIntererestRate(float value)
{
annualInterestRate = value;
}

int main()
{
// Instantiate two different objects of class SavingsAccount, saver1
// and saver2, with balances of $2000.00 and $3000.00, respectively.
SavingsAccount saver1(2000.00);
SavingsAccount saver2(3000.00);

// Set the annualInterestRate to 3%.
SavingsAccount::modifyIntererestRate(3);

// Then calculate the monthly interest and print the new balances for
// each of the savers.
saver1.calculateMonthlyInterest();
cout << "Saver 1 Savings Balance: $" << saver1.GetBalance() << endl;
saver2.calculateMonthlyInterest();
cout << "Saver 2 Savings Balance: $" << saver2.GetBalance() << endl;

cout << endl;

// Then set the annualInterestRate to 4%
SavingsAccount::modifyIntererestRate(4);

// and calculate the next month's interest and print the new balances
// for each of the savers
saver1.calculateMonthlyInterest();
cout << "Saver 1 Savings Balance: $" << saver1.GetBalance() << endl;
saver2.calculateMonthlyInterest();
cout << "Saver 2 Savings Balance: $" << saver2.GetBalance() << endl;

cout << endl;
return 0;
}