Incorrect data input with fstream

问题

I tried to read in data from a text file using fstream but got wrong data.

ifstream fin ("C:\\Users\\rEgonicS\\Documents\\test.in");
int number;
fin >> number;
cout << number;

test.in is simply 12.
cout reads 4273190.
Can someone explain why this is so and how to fix it?

回答1:

The most likely cause is that the file open failed. Check the status after opening, and also after reading; for a simple test, do something like this:

ifstream fin ("C:\\Users\\rEgonicS\\Documents\\test.in");
if (!fin) cout << "File open failed\n";
int number;
fin >> number;
if (!fin) cout << "File read failed\n";
cout << number;

This might give a further clue as to what's going on.

来源：https://stackoverflow.com/questions/3095339/incorrect-data-input-with-fstream