Use a static data member to track the annual interest rate for each of the savers. - C++ Class

C++ examples for Class:static member

  1. HOME
  2. C++
  3. Class
  4. static member

Description

Use a static data member to track the annual interest rate for each of the savers.

Demo Code

                                                                                                                                                        
#include <iostream>
                                                                                                                                                        
class SavingsAccount {
 public://from  w  ww. j  a v  a 2s  .  c o m
    explicit SavingsAccount(double, double = 0.0f);
                                                                                                                                                        
    void calculateMonthlyInterest();
                                                                                                                                                        
    static void modifyInterestRate(double);
    static double getInterestRate();
                                                                                                                                                        
    friend std::ostream& operator<<(std::ostream& out, SavingsAccount acc) {
        return acc.printBalance(out);
    }
                                                                                                                                                        
    std::ostream& printBalance(std::ostream&) const;
                                                                                                                                                        
 private:
    static double annualInterestRate;
    double savingsBalance;
};
                                                                                                                                                        
#include <stdexcept>
                                                                                                                                                        
double SavingsAccount::annualInterestRate = 0.0f;
                                                                                                                                                        
SavingsAccount::SavingsAccount(double bal, double rte) : savingsBalance(bal) {
    try {
        modifyInterestRate(rte);
    } catch (std::invalid_argument& e) {
        std::cout << "Unable to initialize object: " << e.what() << std::endl;
    }
}
void SavingsAccount::calculateMonthlyInterest() {
    savingsBalance += ((savingsBalance * annualInterestRate) / 12.0f);
}
double SavingsAccount::getInterestRate() { return annualInterestRate; }
void SavingsAccount::modifyInterestRate(double rte) {
    if (rte >= 0.0f)
        annualInterestRate = rte;
    else
        throw std::invalid_argument("Interest rate cannot be negative");
}
std::ostream& SavingsAccount::printBalance(std::ostream& out) const {
    out << savingsBalance;
                                                                                                                                                        
    return out;
}
                                                                                                                                                        
int main(int argc, const char* argv[]) {
    SavingsAccount saver1(2000.00f);
    SavingsAccount saver2(3000.00f, 0.03f);
    SavingsAccount saver3(5000.00f, -0.12f);
                                                                                                                                                        
    std::cout << "Interest rate at 3%" << std::endl;
                                                                                                                                                        
    std::cout << "saver1 initial balance: " << saver1 << std::endl;
    saver1.calculateMonthlyInterest();
    std::cout << "after calculateInterestRate " << saver1 << std::endl;
    std::cout << "saver2 initial balance: " << saver2 << std::endl;
    saver2.calculateMonthlyInterest();
    std::cout << "after calculateInterestRate " << saver2 << std::endl;
                                                                                                                                                        
    SavingsAccount::modifyInterestRate(0.04f);
                                                                                                                                                        
    std::cout << "\nInterest rate at 4%" << std::endl;
                                                                                                                                                        
    std::cout << "saver1 initial balance: " << saver1 << std::endl;
    saver1.calculateMonthlyInterest();
    std::cout << "after calculateInterestRate " << saver1 << std::endl;
    std::cout << "saver2 initial balance: " << saver2 << std::endl;
    saver2.calculateMonthlyInterest();
    std::cout << "after calculateInterestRate " << saver2 << std::endl;
                                                                                                                                                        
    try {
        SavingsAccount::modifyInterestRate(-0.12f);
    } catch (std::invalid_argument& e) {
        std::cout << e.what() << std::endl;
    }
                                                                                                                                                        
    return 0;
}

Result


Related Tutorials