I'm reading in a file name from the keyboard and opening the specified file. However it is not meeting my if statement that determines if it's open or not. Heres my code:
#include "prog.hh"
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
string fileName;
cout << "Enter the file name to be read: ";
cin >> fileName;
ifstream input_file("fileName");
std::string line_; // string which text file contents will be stored in
if(input_file.is_open()){ // validation to see if the file is open
while(getline(input_file, line_)){
std::cout<<line_<< '\n'; //prints the contents of the file into the console
}
input_file.close();
}
else {
std::cout<<"File is not open"<< '\n';
}
std::cin.get();
After being compiled, I type in the file name I want to open and I get back the else message "File is not open", although the ifstream should of opened it. I definitely have the right file I'm trying to open in the correct folder. Any help appreciated, thanks.
change
ifstream input_file("fileName");
to
ifstream input_file(fileName);
Related
I am trying to open a csv file in C++ using ifstream with a directory in the file path name. The file does reside in the specified directory location, but I observe an for the variable inFile when executing the code. My research up to this point says the code is correct, but something obviously is wrong. Any suggestions?
Thanks,
KG
#include <string>
#include <fstream>
#include <iostream>
virtual void run()
{
string file_dir = "/home/datafiles/";
string csvFile = file_dir + "/myFile.csv";
ifstream inFile;
inFile.open("csvFile", ios::in);
// file check to see if file is open
if(!inFile.is_open()) {
cout << "error while opening the file" << endl;
}
}
I found the answer to my csv file opening problem, a colleague assisted.
#David - You suggested removing the double quotes in the "inFile.open" line of code. In addition to removing the double quotes, I also needed to add c_str(), which "returns a pointer to a null-terminated character array with data equivalent to those stored in the string," .data() also performs the same function (cppreference.com).
#user4581301 - I am also aware that ios::in is implied with a ifstream, only included it here as a reference; thanks.
The modified code is listed below:
#include <string>
#include <fstream>
#include <iostream>
virtual void run()
{
string file_dir = "/home/datafiles/";
string csvFile = file_dir + "/myFile.csv";
ifstream inFile;
inFile.open(csvFile.c_str(), ios::in);
// file check to see if file is open
if(!inFile.is_open()) {
cout << "error while opening the file" << endl;
}
}
Really appreciate all the help.
Enjoy,
KG
Is this what you're trying to do?
#include <iostream> // std::{ cout, endl }
#include <string> // std::{ string, getline }
#include <fstream> // std::ifstream
auto main() -> int {
// Just to demonstrate.
// You want to use your real path instead of example.cpp
auto file = std::ifstream("example.cpp");
auto line = std::string();
while ( std::getline(file, line) )
std::cout << line << '\n';
std::endl(std::cout);
}
Live example
I am using visual studio 2017
I am new to c++ and here I tried to open a txt file, and confirming that it was opened.
#include <iostream>
#include <fstream>
#include <String>
using namespace std;
int main()
{
ifstream infile;
string text;
infile.open("C:\\Users\\gab_a\\source\\repos\\one\\testing.txt");
if (!infile.is_open()) {
cerr << "Specified file could not be found ";
exit(1);
}
else {
cout << "Opened file ";
infile >> text;
cout << text;
}
return 0;
}
it says that it opened it, and it even read the text that was inside the file, but the actual file isn't opening, I even put the file in the same directory as the project. There are also no errors, so why isn't my file opening?
What you're doing is reading the data from the file into a stream. This is not the same as executing a program to open the file. To do that is generally OS specific, but if you're on Windows you can use ShellExecute or CreateProcess. I do suggest you brush up on your C++ a bit - no offense intended
I used this code to try to open and read the file (not empty), but ifstream did not work - it could not open the file: I addded the check on file opening and it showed, that ifstream even did not (could not) open the file.
I gave administrator rights to the program, but ifstream still could not read the file.
I also tried to find a path, where ifstream would read this file, but I did not success, and at last I tried to open file using the absolute path - but result is the same.
The file is situated in the root folder of the program, but I placed it everywhere and nothing changed.
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
int main() {
string s;
ifstream file("fix.txt");
if (file)
cout << "SUCCESSFULL OPENING" << endl;
while (getline(file, s)) {
cout << s << endl;
s += "+";
cout << s << endl;
}
file.close();
return 0;
}
You may have access to a more detailed error code by activating exceptions on the stream via
file.exceptions(std::ios_base::failbit);
Then, you get more details by writing
try {
file.open("fix.txt");
}
catch(std::ios_base::failure& f) {
// f.what() contains a message, f.code() returns a std::error_code
}
I have written this code. I want to ask from user the full path of a file and then go to that path and open file. But unfortunately the program cannot find the file. for excample I have created a file in this path G:\project 2\newfile but when I type this in the c++ console it says that "Error while opening the file". I really need to solve this problem. please help me with this. thanks
#include <iostream>
#include <fstream>
#include <conio.h>
#include <windows.h>
using namespace std;
int main()
{
string address;
cout << "Enter the full path of the file" << endl;
cin >> address;
ifstream file(address.c_str());
if (!file) {
cout << "Error while opening the file" << endl;
return 1;
}
return 0;
}
Your application is failing because you aren't properly handling spaces in the filename.
Try this instead of cin >> address;:
getline(cin,address);
See this question for the difference between cin and getline.
When I debug this I can see it opens datafile1 , it reads the firstline and
in the logfile I get roma-3-4.log
It change to c:/temp/roma-3-4.log but when I want to open it , it fails. I have check that the _Mystate = 2 .
What is the meaning of that
Thanks
in the transfersubs.cfg there is this
roma-3-4.log
** In the directory c:/temp/ I have the following file
roma-3-4.log
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
using namespace std;
int main()
{
string input;
string logfile;
string errorfile;
short logfilesize1;
fstream dataFile1("c:/temp/transfersubs.cfg", ios::in);
if (dataFile1)
{
getline(dataFile1, input, '$');
logfile=input;
logfilesize1=input.size();
errorfile=input;
errorfile[logfilesize1-4]='e';
errorfile[logfilesize1-3]='r';
errorfile[logfilesize1-2]='r';
logfile="C:/Temp/"+logfile;
fstream dataFile2( logfile, ios::in);
if (dataFile2)
{
dataFile2.close();
}
else
{
cout << "ERROR: Cannot open logfile.\n";
}
dataFile1.close();
}
else
{
cout << "ERROR: Cannot open file.\n";
}
system("Pause");
return 0;
}
I believe your getline doesn't bother looking the newline but only for a $. You didn't post the file you are reading from, but check to ensure it has a $ at the end of the file name otherwise it will fetch the entire file.
It appears that unless you put a \n or endl after writing to the file using ofstream, ifstream won't be able to read anything from the file. In fact, adding a space after whatever you've written into file won't help either.
So always add a newline right after whatever it is that you've written to file using ofstream.