我正在编写的程序是假设列出每个学生支付的所有款项,显示已支付和未支付的金额。
但是问题是由于某些我似乎无法找到的原因它无法正确显示。
payment.txt文件内容顺序如下: 学生代码金额类型(空白表示现金)
11 50
12 25 4543 2323 2321
12 25 Barclays
13 100
14 100
15 50 4545 6343 4342
15 25 HSBC
16 100
17 100
18 100
19 100
20 25 4546 3432 3211
21 75
22 100 Lloyds
23 100
这是到目前为止的代码:
void payment()
{
// Display message asking for the user input
std::cout << "\nList all payment made by each student, show amount paid and outstanding." << std::endl;
// Read from text file and Display list of payment
std::ifstream infile; // enable to open, read in and close a text file
float StudentCode; // to store the student enrolment number
float Amount; // to store the amount of money
float Type; // to store information on type of payment made
float Outstanding; // to store amount of money is due
std::map<int, float> amountsPaid;
infile.open("Payment.txt"); // open a text file called Payment
if (!infile)
{
std::cout << "List is empty" << std::endl; // if the file is empty it output the message
}
else
{
// Display Headings and sub-headings
std::cout << "\nList of Payment: " << std::endl;
std::cout << "" << std::endl;
std::cout << "Enrolment No." << " " << "Amount" << " " << "Outstanding" << std::endl;
// accumulate amounts
while (infile >> StudentCode >> Amount)
{
amountsPaid[StudentCode] += Amount;
}
// loop through map and print all entries
for (auto i = amountsPaid.begin(); i != amountsPaid.end(); ++i)
{
float outstanding = 100 - i->second;
// Display the list of payment made by each student
std::cout << i->first << " " << i->second << " " << "$: " << outstanding << '\n' << std::endl;
}
}
infile.close(); // close the text file
}
它在运行时显示以下内容:
11 50 $50 12 25 75 美元 2321 12 88 美元 4543 2323 $-2223
您能帮忙解释一下为什么要这样做吗? 谢谢
最佳答案
代码的关键部分在这里。
while (infile >> StudentCode >> Amount)
{
amountsPaid[StudentCode] += Amount;
}
这个循环拉取成对的数字。这些是从流中删除的对:
11 50 12 25 4543 2323 2321 12
At that point the text Barclays
is encountered and so the while loop terminates. That is because the text cannot be converted into a float
.
To solve your problem you will need to switch to line oriented processing. Use getline()
to pull off a line at a time. And then break the line into distinct items. One possible solution would be like so:
string line;
while (getline(infile, line))
{
istringstream strm(line);
strm >> StudentCode >> Amount;
amountsPaid[StudentCode] += Amount;
}
关于C++ 程序无法正确显示文本文件中的内容,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/13867895/