Question

7.3 (The Account class) Design a class named Account that contains:
■ A private int data field named id for the account.
■ A private float data field named balance for the account.
■ A private float data field named annualInterestRate that stores the current
interest rate.
■ A constructor that creates an account with the specified id (default 0), initial
balance (default 100), and annual interest rate (default 0).
■ The accessor and mutator methods for id, balance, and annualInterestRate.
■ A method named getMonthlyInterestRate() that returns the monthly
interest rate.
■ A method named getMonthlyInterest() that returns the monthly interest.
■ A method named withdraw that withdraws a specified amount from the
account.
■ A method named deposit that deposits a specified amount to the account.
Draw the UML diagram for the class, and then implement the class. (Hint: The
method getMonthlyInterest() is to return the monthly interest amount, not
the interest rate. Use this formula to calculate the monthly interest: balance *
monthlyInterestRate. monthlyInterestRate is annualInterestRate
/ 12. Note that annualInterestRate is a percent (like 4.5%). You need to
divide it by 100.)
Write a test program that creates an Account object with an account id of 1122, a
balance of $20,000, and an annual interest rate of 4.5%. Use the withdraw
method to withdraw $2,500, use the deposit method to deposit $3,000, and print
the id, balance, monthly interest rate, and monthly interest.

Answer 1

/*UML Diagram

   Account
-accountId : int
-accountBalance : float
-annualInterestRate : float

+Account(int id , float balance, float interestRate)
+setId(int id) : void
+setBalance(float balance) : void
+setInterestRate(float interestRate) : void
+getId() : int
+getBalance() : float
+getInterestRate() : float
+getMonthlyInterestRate() : float
+getMonthlyInterest() : float
+withdraw(float amount) : bool
+deposit(float amount) : void
*/

//C++ program

#include<iostream>
using namespace std;

class Account{
   private:
       int accountId;
       float accountBalance;
       float annualInterestRate;
      
   public:
       Account(int id=0 , float balance=100 ,float interestRate=0) {
           accountId = id;
           accountBalance = balance;
           annualInterestRate = interestRate;
       }
      
       void setId(int id){
           accountId = id;
       }
       void setBalance(float balance){
           accountBalance = balance;
       }
       void setInterestRate(float interestRate){
           annualInterestRate = interestRate;
       }
       int getId(){
           return accountId ;
       }
       float getBalance(){
           return accountBalance;
       }
       float getInterestRate(){
           return annualInterestRate;
       }
       float getMonthlyInterestRate(){
           return annualInterestRate/12;
       }
       float getMonthlyInterest(){
           return accountBalance*annualInterestRate/1200;
       }
       bool withdraw(float amount){
           if(amount<0||amount>accountBalance){
               cout<<"Invalid amount";
               return false;
           }
           accountBalance-=amount;
       }
       void deposit(float amount){
           accountBalance+=amount;
       }
};

int main(){
   Account account(1122,20000,4.5);
   account.withdraw(2500);
   account.deposit(3000);
  
   cout<<"Account ID : "<<account.getId()<<"\n";
   cout<<"Account Balance : $"<<account.getBalance()<<"\n";
   cout<<"Monthly Interest Rate : "<<account.getMonthlyInterestRate()<<"%\n";
   cout<<"Monthly Interest : $"<<account.getMonthlyInterest()<<"\n";
   return 0;
}

//sample output