[matrim]

Hi,
I'm trying to write a program that computes interest and check fees and then prints a new calculated balance. So far it works okay, but seems like I have a lot of unnecessary work. Can someone help me simplify it down plz?

ps: The premium acct has no check fees, but the standard one does. premium=p, standard=s;
Premium acct gives .05 interest if the account is above 5k or .03 if it is under.

#include <iostream>
#include <conio.h>

using namespace std;


int main()
	{
		double FIVE = 5000.00;
		const double LOW_INTEREST = 0.03;
		const double HIGH_INTEREST = 0.05;
		const double CHECK_FEE = 0.10;
		char acct_type;
		bool okay = true, notOkay = false;
		
		
		do 
		{
		cout << "What type of account is this: " << endl;
		cout << "Type 's' for a standard account: " << endl;
		cout << "Type 'p' for a premium account: " << endl;
		cin >> acct_type;
		
		cin.ignore(80, '\n');
		okay = (acct_type == 's' || acct_type == 'p');
		if (!okay)
			cout << "\nYou entered an invalid account type!" << endl;
		}while(!okay);
		
		double earned_interest;
		double fees;
		double newbalance;
		double balance;
		int checks;
		
		if (acct_type == 'p') {
			
		cout << "Enter in the ending balance for this month: " << endl;
		cin >> balance;
		if (balance >= FIVE)
		earned_interest = balance * HIGH_INTEREST;
		else earned_interest = balance * LOW_INTEREST;
		
		
		if (balance < FIVE) {
		cout << "Enter in the number of checks written this month: " << endl;
		cin >> checks;
		fees = checks * CHECK_FEE;
		
		
		newbalance = balance - fees + earned_interest;
		cout.precision(2);
			cout << "\nThe new ending balance is: " << "$" << fixed << newbalance << endl;
		}else{
		newbalance = balance + earned_interest;
		cout << "\nThe new ending balance is: " << "$" << newbalance << endl;
		}
		}		 
		if (acct_type == 's')
		cout << "Enter in the ending balance for this month: " << endl;
		cin >> balance;
		cout << "Enter in the number of checks written this month: " << endl;
		cin >> checks;
			earned_interest = balance * LOW_INTEREST;
			fees = checks * CHECK_FEE;
			newbalance = balance - fees + earned_interest;
			cout.precision(2);
			cout << "\nThe new ending balance is: " << "$" << fixed << newbalance << endl;
		
		//getch();
		return 0;

[dquigley]

Here's one way to do it that takes advantage of the OOP nature of C++... note that the Account class contains the logic, not the main program loop.

#include <iostream>
#include <conio.h>

using namespace std;

#define LOW_INTEREST 0.03
#define HIGH_INTEREST 0.05
#define CHECK_FEE 0.10
#define FIVE 5000.00

class Account
{
public:

    char m_acct_type;
    double m_balance;
    long m_checks_written;

    Account(char type)
    {
        m_acct_type = type;
        m_balance = 0.0;
        m_checks_written = 0;
    }
    
    bool needChecks()
    {
      return (m_acct_type == 's');
    }

    double Interest()
    {
        if (m_acct_type == 's')
            return 0.0;

        if (m_balance > FIVE)
            return m_balance * (HIGH_INTEREST / 12);
        else
            return m_balance * (LOW_INTEREST  / 12);
    }

    double CheckFees()
    {
        if (m_acct_type == 'p')
            return 0.0;
        else
            return m_checks_written * CHECK_FEE;
    }

    double NewBalance()
    {
        return m_balance - CheckFees() + Interest();
    }

};


int main()
{
    char acct_type;
    bool okay;
    do 
    {
        cout << "What type of account is this: " << endl;
        cout << "Type 's' for a standard account: " << endl;
        cout << "Type 'p' for a premium account: " << endl;
        cin >> acct_type;
        cin.ignore(80, '\n');
        okay = (acct_type == 's' || acct_type == 'p');
        if (!okay)
            cout << "\nYou entered an invalid account type!" << endl;
    } while(!okay);
	
    Account *acct = new Account(acct_type);
	
    cout << "Enter in the ending balance for this month: " << endl;
    cin >> acct->m_balance;

    if (acct->needChecks())
    {
        cout << "Enter in the number of checks written this month: " << endl;
        cin >> acct->m_checks_written;
    }
    cout.precision(2);
    cout << "\nBeginning balance : " << "$" << fixed << acct->m_balance << endl;
    cout << "\n         Interest : " << "$" << fixed << acct->Interest() << endl;
    cout << "\n       Check fees : " << "$" << fixed << acct->CheckFees() << endl;
    cout << "\n      New balance : " << "$" << fixed << acct->NewBalance() << endl;

    delete acct;
    return 0;
}

Best,
Dan

[matrim]

Thanks for that. If you could for a minute, assume I've not had information about classes yet, but have had only the beginnings of code( we haven't covered classes yet I mean), what do you think then? Does my code work okay?

[dquigley]

Well no... there are several issues.

1) You are charging interest on a monthly basis. Interest is usually charged yearly. action:divide the interest charges by 12

2) The logic requires that the user answers the question "Enter in the number of checks written this month: " twice if the account type is P and the balance is under $5,000


Best,
Dan

[Shadow2531]

An example using functions and validating input:

#include <cstdio>
using namespace std;

char getType() {
    while ( 1 ) {
        printf("\n(s)tandard or (p)remium account? ");
        const char type( getchar() );
        fflush( stdin );    
        if ( type == 's' || type == 'p' ) {
            return type;
        }
        printf("\nInvalid account type!\n");
    }
}

double getBalance() {
    while ( 1 ) {
        printf("\nEnding balance for this month? $");
        double balance;
        const int good( scanf("%lf", &balance ) );
        fflush(stdin);
        if ( good ) {
            return balance;
        }
        printf("\nInvalid balance!\n");
    }
}

int getChecks() {
    while ( 1 ) {
        printf("\nNumber of checks written this month? ");
        int checks;
        const int good( scanf( "%d", &checks ) );
        fflush(stdin);
        if ( good && checks > -1 ) {
            return checks;
        }
        printf("\nInvalid number of checks\n");
    }
}

int main() {
    const char type( getType() );
    double balance( getBalance() );
    if ( type == 'p' && balance >= 5000.00 ) {
        balance += balance * 0.05 / 12;
    } else {
        balance += balance * 0.03 / 12;
        if ( type == 's' ) {
            balance -= getChecks() * 0.10;
        }
    }
    printf("\nNew ending balance is $%.2f\n", balance );
}

Basically, if you're going to check your account type input to make sure it's right, you should check the others inputs also. I did it with the C functions getchar(), scanf() and fflush() etc. to handle bad input instead of cin.good(), cin.clear() and cin.ignore() etc. It's just easier with the former, but use whatever you're supposed to. ( You should really use std::string and getline(cin,string) to grab input, validate it and convert when necessary, but that's overdoing it for this.)

You want to only ask for each input once instead of multiple times and as already said, if that's the rate for the whole year, you need to divide.

If that doesn't produce your desired output, change it to do so of course.