[英]Reading data from a text file into an array of structs
我之前已经看过这个问题,但是找不到可以帮助我解决问题的答案。 这里发生了一些事情。 这将显示一个菜单,该菜单将允许用户:
此信息将保存到应输入和输出到的数据文件中。 尝试查看文件中的数据时,第一个菜单选项有问题。 假设已经有一个包含以下信息的数据文件C:\\danceexpenses.txt
:
DJ
100
Site
100
Food
100
Favors
100
Security
100
Ticket printing
100
Etc.
100
etc.
100
该程序将不会显示该信息。 每个都只给出一个空白行。 我需要添加一些东西来配置输出吗?
void charges()
{
//Structures to hold data
struct Expenses
{
string name;
double cost;
};
int chargesChoice;
const int CHARGES_MENU_VIEW = 1, CHARGES_MENU_UPDATE = 2, CHARGES_MENU_QUIT = 3;
const int NUM_EXPENSES = 8; //number of expenses
Expenses danceExpenses[NUM_EXPENSES]; //array of structures
int index; //loop counter
cout << "\nWhat would you like to do?\n\n"
<< "1. View charges\n"
<< "2. Update charges\n"
<< "3. Return to main menu\n"
<< "Enter your choice: ";
cin >> chargesChoice;
while (chargesChoice < CHARGES_MENU_VIEW || chargesChoice > CHARGES_MENU_QUIT)
{
cout << "\nPlease enter a valid menu choice: ";
cin >> chargesChoice;
}
switch (chargesChoice)
{
case CHARGES_MENU_VIEW: //Display the expenses data
myFile.open("c:\\danceexpenses.txt", ios::in); //open file
if (!myFile)
{
cout << "Error opening file. Program aborting.\n";
return;
}
char output[100];
cout << "\nHere are the expected expenses for the dance:\n";
for (index = 0; index < NUM_EXPENSES; index++)
cout << danceExpenses[index].name << endl << endl;
myFile.close(); //close file
break;
case CHARGES_MENU_UPDATE:
//get expense data
myFile.open("c:\\danceexpenses.txt", ios::out); //open file
if (!myFile)
{
cout << "Error opening file. Program aborting.\n";
return;
}
for (index = 0; index < NUM_EXPENSES; index++)
{
cout << "Enter the name of the expense: ";
cin.ignore();
getline(cin, danceExpenses[index].name);
cout << "Enter the expected cost for this expense: ";
cin >> danceExpenses[index].cost;
}
//Write data to file
for (index = 0; index < NUM_EXPENSES; index++)
{
myFile << danceExpenses[index].name << endl;
myFile << danceExpenses[index].cost << endl;
}
myFile.close(); //close file
break;
case CHARGES_MENU_QUIT:
showMenu();
break;
}
charges();
}
如果您的第一个动作是输入1,则代码应输入:
case CHARGES_MENU_VIEW: //Display the expenses data
myFile.open("c:\\danceexpenses.txt", ios::in); //open file
if (!myFile)
{
cout << "Error opening file. Program aborting.\n";
return;
}
char output[100];
cout << "\nHere are the expected expenses for the dance:\n";
for (index = 0; index < NUM_EXPENSES; index++)
cout << danceExpenses[index].name << endl << endl;
myFile.close(); //close file
break;
这将打开舞蹈费用文件,但不会从中读取。 然后,它遍历尚未初始化的费用清单,并关闭输入文件。 还有一个未使用的变量output
。
您需要先将数据读入内存,然后再打印出来。
int num = 0;
while (myFile >> danceexpenses[num].name >> danceexpenses[num].cost)
num++;
for (index = 0; index < num; index++)
cout << danceExpenses[index].name << endl << endl;
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