C++ ifstream is_open() fails [duplicate] - c++

Question

This question already has answers here:
Where to place file in order to read?
(4 answers)
Closed 6 years ago.
Why does my is_open() always fail and goes into the else statement which displays the error message?
Another method of mine is similar to this yet it worked.
#include <iostream>
#include <fstream>
using namespace std;
int main() {
string userName;
cout << "Please login to your account here!" << endl;
cout << "Username: ";
cin >> userName;
ifstream openSalt;
openSalt.open("salt.txt"); //open the file
if(openSalt.is_open()) //if file is open
{
string temp;
while (getline(openSalt,temp))
{
//gets content
//if user exists, login
//else, exit
}
openSalt.close();
}
else
{
cout << "Error opening file!" << endl;
exit(1);
}
return 0;
}

Answer 1

Assuming code is main function etc, the code works for me.
The issue is more likely to be that what ether tool/IDE you are using to compile the program sets the current folder to a different place to what you are expecting, and then is not the place the salt.txt file is in.

Answer 2

Check two things.
If the file really exists in the current folder from where you program is run ?
Do you have correct permissions to open the file ?

Answer 3

use this function to get the error :
std::string GetLastErrorAsString()
{
//Get the error message, if any.
DWORD errorMessageID = ::GetLastError();
if (errorMessageID == 0)
return std::string(); //No error message has been recorded
LPSTR messageBuffer = nullptr;
size_t size = FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, errorMessageID, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPSTR)&messageBuffer, 0, NULL);
std::string message(messageBuffer, size);
//Free the buffer.
LocalFree(messageBuffer);
return message;
}
then call it in your else
else
{
cout << GetLastErrorAsString() << endl;
system("pause");
exit(1);
}
I used your code and it worked, make sure the file is in the same directory, make sure you are not working with a salt.txt.txt file (common mistake)