ifstream won't open file

问题

I'm trying to open a file so I can read from it.

#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;

ifstream input_file("blah.txt", ios::in);
ofstream output_file("output.txt", ios::out);

Bank::Bank(void){
    input_file.open("blah.txt");
    if(!input_file){
        cerr << "Error" << endl;
        exit(1);
    }
    else{
        cout << "good 2 go" << endl;
    }
}

This is the code I have for reading the file named blah.txt and the output I'm getting at the terminal is the "Error". I am using Linux Mint 14 and gVim, so when I enter the :pwd command, I know I am in directory /mnt/share. Checking from the terminal, file blah.txt is in the same directory. The only thing I can think of is hidden file extensions. Why can't I open the file?

回答1:

That's because you open "blah.txt" twice.

First time:

ifstream input_file("blah.txt", ios::in)

Second time:

input_file.open("blah.txt")

Removing the second one should fix your problem.

回答2:

This

ifstream input_file("blah.txt", ios::in);

should open the file:

Additionally, when the second constructor version is used, the stream is associated with a physical file as if a call to the member function open with the same parameters was made.

This

input_file.open("blah.txt");

should fail:

If the object already has a file associated (open), the function fails.

Please read the documentation.

来源：https://stackoverflow.com/questions/14920106/ifstream-wont-open-file

标签

c++

ifstream