现在我的问题似乎集中在saveFile函数上。
我会在这里发布整个程序，所以当看到一大堆代码时不要再烦恼...只看底部的saveFile函数...我发布所有代码JUST IN CASE它会帮助你帮我解决问题。
现在为大家定义明显的问题：我可以在运行控制台应用程序的整个生命周期中使用updateSale函数编辑文件，但是当我使用saveFile函数并输入＆＃39; y＆＃ 39;要保存，使用updateSales函数后可见的差异请勿保存到名为＆＃34; salespeople.txt＆＃34;的实际销售文件中。我不明白为什么。
这就是salespeople.txt的样子： Schrute 25000
Halpert 20000
万斯19000
哈德森17995.5
Bernard 14501.5
现在这是程序：
#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>
using namespace std;
//variables--------------------------------------------------------
int lineCount = 0;
//prototypes-------------------------------------------------------
int getIndexLargest(string[], double[]);
void displaySalesPeople(string[], double[]);
bool readSalesFile(string[], double[]);
void updateSales(string[], double[]);
int saveFile(string, string[], double[], int);
int main()
{
string fileName;
int arrayLength;
ifstream readSales;
string salesPersonName[5];
double saleAmount[5];
bool flag = false;
int options;
do
{
cout << "1) Open sales person file. "<< endl;
cout << "2) Display sales person information. "<< endl;
cout << "3) Update sales. " << endl;
cout << "4) Get best sales person. " << endl;
cout << "5) Exit. " << endl;
cout << "Please enter a number 1-5 to select an option." <<endl;
cin >> options;
if(options == 1)
{
flag = readSalesFile(salesPersonName, saleAmount);
}
else if(options == 2)
{
if(flag == false)
{
cout << "Please open sales file before selecting this option. Try again" << endl;
}
else
displaySalesPeople(salesPersonName, saleAmount);
}
else if(options == 3)
{
if(flag == false)
{
cout << "Please open sales file before selecting this option. Try again" << endl;
}
else
updateSales(salesPersonName, saleAmount);
}
else if(options == 4)
{
if(flag == false)
{
cout << "Please open sales file before selecting this option. Try again" << endl;
}
getIndexLargest(salesPersonName, saleAmount);
}
else if(options == 5)
{
char choice;
cout << "Enter character y to save... anything else will exit without saving: " << endl;
cin >> choice;
if(choice == 'y')
{
saveFile(fileName, salesPersonName, saleAmount, arrayLength);
cout << "File saved. " << endl;
}
else
{
cout << "closing program" << endl;
}
}
}
while(options != 5);
return 0;
}
//functions---------------------------------
bool readSalesFile(string salesPersonName[], double saleAmount[])
{
bool flag = false;
ifstream readSales;
string fileName;
cout << "Please enter the path to your sales people file: ";
getline(cin, fileName);
readSales.open(fileName.c_str());
while(readSales.fail())
{
cout << "Failed. Please enter the path to your sales file again: ";
getline(cin, fileName);
readSales.open(fileName.c_str());
}
if(readSales.good())
{
flag = true;
cout << lineCount;
string name = " ";
double amount =0.00;
int i = 0;
while(!readSales.eof())
{
readSales >> name;
readSales >> amount;
salesPersonName[i] = name;
saleAmount[i] = amount;
i++;
}
for(i = 0; i < 5; i++)
{
cout << "Sales person name: " << salesPersonName[i] << endl;
cout << "Sale amount: $" << saleAmount[i] << endl;
}
readSales.close();
}
readSales.close();
return flag;
}
void displaySalesPeople(string salesPersonName[], double saleAmount[])
{
for(int i = 0; i < 5; i++)
{
cout << "Sales person name: " << salesPersonName[i] << endl;
cout << "Sale amount: $" << saleAmount[i] << endl;
}
}
void updateSales(string salesPersonName[], double saleAmount[])
{
bool flag = false;
string findName;
double moneyAmount;
cout << "Enter name of sales person you want to modify: " << endl;
cin >> findName;
for(int i = 0; i < 5; i++)
{
if(findName == salesPersonName[i])
{
cout << "Enter the sale amount you would like to modify: " << endl;
cin >> moneyAmount;
saleAmount[i] += moneyAmount;
cout << saleAmount[i] << endl;
flag = true;
}
}
if(flag == false)
{
cout << " name not found" << endl;
}
}
int getIndexLargest(string salesPersonName[], double saleAmount[])
{
ifstream readSales;
while(!readSales.eof())
{
double largestSale = 0.00;
string largestSalesPerson;
int i = 0;
lineCount++;
readSales >> salesPersonName[i];
readSales >> saleAmount[i];
if(saleAmount[i] > largestSale)
{
largestSale = saleAmount[i];
largestSalesPerson = salesPersonName[i];
}
cout << "Best sales person : "<< largestSalesPerson << " $" <<setprecision(2)<<fixed<< largestSale << endl;
}
}
int saveFile(string fileName, string salesPersonName[], double saleAmount[], int arrayLength)
{
ofstream saveFile(fileName.c_str());
saveFile.open(fileName.c_str());
for(int i = 0; i < 5; i++)
{
saveFile << salesPersonName[i] << " " << saleAmount[i] << endl;
}
saveFile.close();
return 0;
}
答案 0 :(得分：2)
您试图打开文件两次：
ofstream saveFile(fileName.c_str()); // this opens the file
saveFile.open(fileName.c_str()); // so does this
这会使文件处于错误状态，因此不会发生写入。
这样做：
ofstream saveFile(fileName.c_str()); // this opens the file
这应该有效。
或者你可以这样做：
ofstream saveFile; // this does not open the file
saveFile.open(fileName.c_str()); // but this does
这也应该有效。