c++ - 类循环

Question

在我的“computeInterest()”函数中，我需要一个循环来显示先前用于从“enterAccountData()”填充数组的帐号，我会使用一个嵌套循环来查看帐号吗？还是只有一个循环？

提前感谢您的帮助，这是我的代码。

#include <iostream>
#include <iomanip>

using namespace std;

class BankAccount
{
private:
int accountNum;
double accountBal;
static const double annualIntRate;
public:
double enterAccountData(int, double);
void computeInterest();
void displayAccount();
 };
 //implementation section:
const double BankAccount::annualIntRate = 0.03;
double BankAccount::enterAccountData(int number, double balance)
{
cout << setprecision(2) << fixed;



cout << "Enter the account number " << endl;
cin >> number;
accountNum = number;
while(number < 0 || number < 1000)
{
    cout << "Account numbers cannot be negative or less than 1000 " <<
        "Enter a new account number: " << endl;
    cin >> number;
}

cout << "Enter the account balance " << endl;
cin >> balance;
accountBal = balance;
while(balance < 0)
{
    cout << "Account balances cannot be negative. " <<
        "Enter a new account balance: " << endl;
    cin >> balance;
}
return balance,number;
}
void BankAccount::computeInterest()
{
const int MAX_ACCOUNTS = 10;
const int MONTHS_IN_YEAR = 12;
int months;
double rate = 0; 
int counter = 0;

cout << "How many months will the account be held for? ";
cin >> months;
counter = 0;
do
{
 accountBal = accountBal * annualIntRate + accountBal;
 counter++;
}while(months > counter);
/*for(counter = 0; counter < MAX_ACCOUNTS; counter++)
{
    cout << "Account # " << counter << "Balance is:$" << accountBal << endl;
}*/

}

int main()
{
const int QUIT = 0;
const int MAX_ACCOUNTS = 10;
int counter;
int input;
int number = 0;
double balance = 0;

BankAccount accounts[MAX_ACCOUNTS];
//BankAccount display;

counter = 0;

do
{
    accounts[counter].enterAccountData(number, balance);
    cout << " Enter " << QUIT << " to stop, or press 1 to proceed.";
    cin >> input;
    counter++;

}while(input != QUIT && counter != 10);

for(counter = 0; counter < MAX_ACCOUNTS; counter++)
{
    accounts[counter].computeInterest();
}
system("pause");
return 0;
}

我注释掉了一个 for 循环，我之前厌倦了它不起作用。

Answer 1

您不需要循环。即使使用循环，也总是打印相同的值。

为什么？

该程序有 10 个 BankAccount 实例，这意味着每个实例都有自己的类成员拷贝。

const int MAX_ACCOUNTS = 10;
const int MONTHS_IN_YEAR = 12; // Both of these declared global

而在main()中，如果需要显示所有账户信息——

for(int i = 0; i < MAX_ACCOUNTS; ++i)
{
    accounts[i].displayAccount(); // Where in displayAccount definition is to display accountNum and accountBal
}

而如果在BankAccount::ComputeInterest()中，需要显示账户信息-

void BankAccount::ComputeInterest() 
{


    // ......

    std::cout << "\n Acc. Num:\t " << accountNum << "\t Acc. Bal:\t" << accountBal << "\n";

}

BankAccount::ComputeInterest() 不采用任何引用其他实例的参数。因此，它具有仅调用它的对象信息。并且可以更好地组织程序。

变量有不必要的重复(即 MAX_ACCOUNTS 等)

double BankAccount::enterAccountData(int number, double balance) 返回类型为 double。

double BankAccount::enterAccountData(int number, double balance)
{
     // ....

     return balance,number;
}

return 永远不会返回多个值。返回最后一个变量的值。因此，仅返回 number。