文件打开以便在C ++中阅读

Question

I am developing a project in Visual Studio 2012 and I can not figure out why this code always return with "The file can not be opened!", because tram.exe and stops.txt is in the same (Debug) folder.

#include <iostream>
#include <fstream>

int main (int count, char *arguments[]) {
    if (count > 1) {
        ifstream input("stops.txt");

        if (input.is_open()) {

        } else {
            cout << "The file can not be opened!";
        }
    }
}

Answer 1

Visual Studio, by default, will set your Working Directory to $(ProjectDir) - that is, the folder where your vcxproj lives - this won't be the same as the folder your exe gets written out to, so you won't find your text file in the current directory.

Either manually change the working directory Project Properties->Configuration Properties->Debugging to match the target path, or change your filename to point to the full (or relative) path.

Answer 2

Find out what the current working directory of your running process is with

http://msdn.microsoft.com/en-us/library/windows/desktop/aa364934(v=vs.85).aspx

Example:

unsigned int length = 0;
char* workingDirectory;

length = GetCurrentDirectory(0, NULL); // How large should my buffer be?
workingDirectory = new char[length]; // Allocate buffer
GetCurrentDirectory( (DWORD) length, (LPTSTR) workingDirectory); // Fill with string
std::cout << workingDirectory << std::endl; // Output string
delete [] workingDirectory; // Make sure to delete it

You can put this into a function

void getWorkingDirectory(std::string& dir)
{
    unsigned int length = 0;
    char* buffer;
    length = GetCurrentDirectory(0, NULL);
    buffer = new char[length];
    GetCurrentDirectory( (DWORD) length, (LPTSTR) buffer);
    dir = buffer;
    delete [] buffer;
}

NOTE: I haven't tested this.

Answer 3

Use the below line of code:

ifstream input("stops.txt", std::fstream::out);

Its working.