c++ - 初始化变量时遇到问题

Question

下面是我正在编写的代码，用于学习如何在 C++ 中使用文件。我的所有读写都正确，但我无法让我的显示器显示正确的值，因为当我尝试在 while 循环中初始化 Total 变量时它被忽略了。

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

int main()
{
    int customerNumber;
    double beginningBalance, purchase, payments, financeCharge, endingBalance;
    double beginningTotal, purchaseTotal, paymentsTotal, financeChargeTotal, endingTotal;
    ifstream inputFile;
    ofstream outputFile;

    inputFile.open("BeginningBalance.dat");
    outputFile.open("EndingBalance.dat");
    cout<<"Cust No | Beginning Bal | Finance Charge | Purchases | Payments | Ending Balance"<<endl;

    while (inputFile >> customerNumber)
    {
        outputFile <<customerNumber<<endl;
        inputFile >> beginningBalance;
        inputFile >> purchase;
        inputFile >> payments;

        financeCharge = beginningBalance * .01;
        endingBlanance= beginningBalance + purchase + financeCharge - payments;

        //***********************************************
        //This is where I am having trouble initializing variables.
        //***********************************************
        beginningTotal += beginningBalance; //beginningTotal not being intitialized.
        financeChargeTotal += financeCharge;
        purchaseTotal += purchase;
        paymentsTotal += payments;
        endingTotal += endingBalance;

        outputFile <<fixed<<setprecision(2)<<endingBalance<<endl;

        cout<<setw(5)<<customerNumber<<fixed<<setprecision(2)<<"        "<<beginningBalance<<"        "<<financeCharge<<"          "<<purchase<<"       "<<payments<<"       "<<endingBalance<<endl;
    }
    cout<<"Total:    "<<fixed<<setprecesion(2)<<beginningTotal<<"   "<<financeChargeTotal;
    system ("PAUSE");
    return 0;
}

Answer 1

您没有首先初始化您的变量，因此它们没有任何初始值。然后你向这些变量添加一些东西，结果是未定义的(读取垃圾)。

考虑像这样声明它们:

double beginningTotal = 0, purchaseTotal = 0, paymentsTotal = 0, financeChargeTotal = 0, endingTotal = 0;

...甚至更好 - 为它们创建一些结构。