I am working on a text processor that takes in text from a file and inserts it into a Graph data structure. I made the Graph, but I am having trouble with the text processor. Whenever I execute the code, it says I am unable to open the file. I made sure that the text file was in the same directory when I executed the code. Here is the code for the GraphTextProcessor class:
#include <fstream>
#include <cstring>
#include <string>
#include "Graph.h"
class GraphTextProcessor {
private:
Graph* m_data;
public:
GraphTextProcessor();
Graph* process(std::string filename);
};
GraphTextProcessor::GraphTextProcessor() {
}
Graph* GraphTextProcessor::process(std::string filename) {
//process text file and insert into graph here
std::string word;
//opens file in read mode
std::ifstream readFile;
readFile.open(filename.c_str(), std::ios::in);
if (readFile.is_open()) { //Not opening
while (readFile >> word) {
std::cout << word << std::endl;
}
// Closes open text file
readFile.close();
}
else {
std::cout << "Unable to open text file." << std::endl;
}
return NULL;
}
I am just trying to read from a file first before I actually try writing to the Graph. Here is the code that I am running in Main:
#include <iostream>
#include <string>
#include "GraphTextProcessor.h"
int main() {
GraphTextProcessor *gp = new GraphTextProcessor();
gp->process("hello.txt");
}
It prints "Unable to open text file". Any suggestions?
I ran the code myself and it is working fine.
List your programming environment and what steps did you follow.Please make your question more elaborate and explain exactly what have you tried for making it work.
Please make sure the following:
Try using the full path name; for example,
ifstream in("C:/someDirectory/andSomeOtherDirectory/one.txt");
Try changing the spelling of the file.
For example:
"One.txt"
or
"ONE.txt"
You need permission to read the file. Try changing the permission of file.
Try different compilers
Also if you use exception handling (try, throw, catch) instead of if, else that will help finding the error.
Related
Im new to c++ and i was trying to open a ".txt" file using ifstream. the file im using is called "ola.txt" which literally just contains two lines of text without punctuation just plain and simple text. The code that i wrote is this
#include <iostream>
#include <vector>
#include <fstream>
#include <iomanip>
#include <string>
using namespace std;
int main()
{
int x;
string line;
vector<int> vect;
ifstream inFile("C:\\Users\\ruial\\Desktop\\ola.txt");
inFile.open("C:\\Users\\ruial\\Desktop\\ola.txt");
if (inFile.is_open()) {
while (getline(inFile, line))
{
cout << line << '\n';
}
inFile.close();
}
else {
cout << "Unable to open file";
exit(1); // terminate with error
}
return 0;
}
The path to the file that i wrote is correct such that the file opens, but when the program runs it doesn´t cout the lines that i wrote on the txt file to the cmd, i dont know if this is somewhat important but im coding in visual studio 2019.
I can't seem to find the answer to this problem anywhere in the internet and to be honest i think im doing it right, any help would be much appreciated,thanks in advance.
You are trying to open the inFile twice. First time during inFile construction, ifstream inFile("C:\\Users\\ruial\\Desktop\\ola.txt"), second time you try to open it again with inFile.open("C:\\Users\\ruial\\Desktop\\ola.txt"), when it's already open, which is erroneous, and flags the stream as no longer good.
3 possible fixes:
Remove inFile.open("C:\\Users\\ruial\\Desktop\\ola.txt")
Use default constructor, without specifying the file name
inFile.close() before you open it again (obviously, not the nicest fix).
I'm trying to read a text file and output the contents. It's just I can't seem to find the right method and the ones I've used (including this one), seems to wipe the text file. The code:
std::string Line;
std::ifstream File("Account.txt");
if (File.is_open()) {
while (getline(File, Line)) {
std::cout << Line << std::endl;
}
}
else {
std::cout << "Unable to open File" << std::endl;
}
File.close();
I'm also using:
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
I'm using this code (below) every time the program runs to create the file which might be the error, if so can anyone recommend a way to create the file only if it doesn't already exist
std::ofstream File("Account.txt");
File.close();
Your file is being wiped by your file creating code.
std::ofstream File("Account.txt");
File.close();
To create a file without wiping existing contents try this
std::ofstream File("Account.txt", std::ios_base::app);
File.close();
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'm new to C++ and am trying to open a file, but can't get it to work. The file is definitely there, in the same directory. I have tried unhiding extensions (it's definitely called test.txt and not test.txt.txt for example), and also tried using the full path. The file is not open anywhere. Any ideas (I'm sure it's something simple but I'm stuck)?
string mostCommon(string fileName)
{
string common = "default";
ifstream inFile;
//inFile.open(fileName.c_str());
inFile.open("test.txt");
if (!inFile.fail())
{
cout << "file opened ok" << endl;
}
inFile.close();
return common;
}
If you specify inFile.open("test.txt") it will try to open "test.txt" in the current working directory. Check to make certain that is actually where the file is. If you use absolute or relative pathing, make sure that you use '/' or '\\' as the path separator.
Here is an example that works when a file exists:
#include <fstream>
#include <string>
#include <cassert>
using namespace std;
bool process_file(string fileName)
{
ifstream inFile(fileName.c_str());
if (!inFile)
return false;
//! Do whatever...
return true;
}
int main()
{
//! be sure to use / or \\ for directory separators.
bool opened = process_file("g:/test.dat");
assert(opened);
}
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.