c++ - 使用数组的文件输出不正确

Question

大家好，我刚刚开始学习我的第一门编程语言，并且刚刚更正了我的代码中的一个错误，结果又留下了另一个错误。值得庆幸的是，这是我需要解决的最后一个问题，但我自己做起来有点麻烦。

程序是读入一个客户编号和每个客户编号相关的费用。然后它会添加财务费用，输出所有费用，汇总所有内容，并以相反的顺序保存每个客户的新余额以及他们的 ID 号以归档。

beginningbalance.dat 看起来像

111
200.00
300.00
50.00
222
300.00
200.00
100.00

和 newbalances.dat 应该看起来像

222
402.00
111
251.00

除了取决于在文件写入循环中放置“count--”的位置，我最终得到了

222
402.00
111
251.00
-858993460
-92559631349317830000000000000000000000000000000000000000000000.00

我不知道我应该怎么做才能摆脱这些额外的值(value)。有什么建议吗？

这是我的代码

#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;



int main()
{
  int count = 0;
  const int size = 100;
  double customer_beg_balance, customer_purchases, customer_payments, finance_charge_cost, finance_charge = .01;
  int customer_number[size];
  double new_balance[size];
  double total_beg_balances=0,total_finance_charges=0,total_purchases=0,total_payments=0,total_end_balances=0;


  ifstream beginning_balance;
  beginning_balance.open("beginningbalance.dat");

  while(beginning_balance>>customer_number[count])
    {
        beginning_balance >> customer_beg_balance;
        beginning_balance >> customer_purchases;
        beginning_balance >> customer_payments;

        finance_charge_cost = customer_beg_balance * finance_charge;

        new_balance[count] = customer_beg_balance + finance_charge_cost + customer_purchases - customer_payments; 
        total_beg_balances+=customer_beg_balance;
        total_finance_charges+=finance_charge_cost;
        total_purchases+=customer_purchases;
        total_payments+=customer_payments;
        total_end_balances+=new_balance[count];

        cout<<fixed<<setprecision(2)<<setw(8)<<"Cust No  "<<"Beg. Bal.  "<<"Finance Charge  "<<"Purchases  "<<"Payments  "<<"Ending Bal.\n"
            <<customer_number[count]<<"        "<<customer_beg_balance<<"        "<<finance_charge_cost<<"       "<<customer_purchases<<"     "<<customer_payments<<"         "<<new_balance[count]<<endl;


        count++;                            
    }

  cout<<"\nTotals     "<<total_beg_balances<<"        "<<total_finance_charges<<"       "<<total_purchases<<"     "<<total_payments<<"         "<<total_end_balances<<endl;

  ofstream new_balance_file;
  new_balance_file.open("NewBalance.dat");

  while(count >= 0)
  {
    count--;
    new_balance_file <<customer_number[count]<<endl;
    new_balance_file<< fixed<<setprecision(2)<<new_balance[count]<<endl;

  }


  new_balance_file.close();


system("pause");
        return 0;
 }

Answer 1

你的条件不对

 while(count >= 0)
 {
    count--;
    new_balance_file <<customer_number[count]<<endl;
    new_balance_file<< fixed<<setprecision(2)<<new_balance[count]<<endl;

 }

应该是 count > 0 而不是 count >= 0。

这样 count 将遍历值 n, n-1, ... 1 并且因为您在 while 语句的开头递减它，您将在其中操作的值您的循环将是 n-1, n-2.... 0，正是您所需要的。

顺便说一句，如果你的类(class)已经涵盖了for循环并且你被允许使用它，那么它更适合，像这样

for(int i = count - 1; i >= 0; --i)
{
    use i instead of count here.
}

希望对你有所帮助，祝你学业顺利!