I am trying to run the following program:
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
ifstream inFile;
ofstream outFile;
double first=1.49, second=2.59, third=3.69, fourth=4.79;
inFile.open("prices.txt");
char response;
if(!inFile.fail())
{
cout << "A file by the name prices.txt exists.\n" << "Do you want to continue and overwrite it\n" << " with the new data (y or n);"; cin >> response;
if(tolower(response) == 'n')
{
cout << "The existing file will not be overwritten." << endl;
return -1;
}
}
outFile.open("prices.txt");
if (inFile.fail())
{
cout << "\n The file does not exist and can not be opened" << endl;
cout << "The file has been successfully opened for output." << endl;
outFile << first << "\n" << second << "\n" << fourth << "\n" << endl;
outFile.close();
exit(1);
cout << "The file has been successfully opened for output. " << endl;
outFile << first << "\n" << second << "\n" << third << "\n" << fourth << endl;
outFile.close();
return 0;
}
}
Yet this program will not write the values to the prices.txt file. If you run the program once it says the file does not exist. Running it a second time says the file is already there and if you want to overwrite it. The thing is searching my Mac I cannot find this file anywhere.
Any ideas what I am doing wrong with running it in Xcode? A friend runs the exact same code in Visual Studio 2008 and it works. Any help is appreciated.
You need to set the working directory for the executable since you are assuming that your data files are in the current working directory. In Xcode 3.x you set this in the first tab of Get Info for the executable. In Xcode 4.x it has been moved, but the principle is the same.
Alternatively you can change your data file paths (e.g. make them absolute) so that you do not make assumptions about the current working directory.
You may not have permission to write into the directory that you are trying to save the file too.
Also, there is an error in your program and I am sure if it is there for debugging reasons. You have
outFile.close();
exit(1);
But then shortly there after you try to write to the file, then close it again.
Related
When I write a simple ofstream and ifstream instance ,ifstream is working but ofstream is not working. When I run this program ofstream is creating but I don't see output.txt in directory file.
I tried turning off COMODO Antivirus but the problem persists.
What is preventing me from seeing the output file?
here my First.cpp:
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
ofstream output("output.txt");
ifstream input("input.txt");
if (output.is_open()) {
cout << "ouput file is open" << endl;
output << "hi";
}
else {
cout << "output file is not open" << endl;
}
int number;
if (input.is_open()) {
cout << "input file is open" << endl;
input >> number;
cout << "Number:" << number << endl;
}
else {
cout << "input file is not open" << endl;
}
input.close();
output.close();
return 0;
}
here my input.txt:
21
12
22
23
32
when I run this program:
ouput file is open
input file is open
Number:21
I see that the issue was related to your Antivirus, but I'll write this anyways for others to read.
When dealing with IO its important to know what directory your executable will execute from. The working directory can be set in the project configuration. Right Click the project > Properties > Configuration Properties > Debugging > Working Directory. Configuration Window
The working directory is also the directory where all your application created files will be generated. For instance the example code generate output.txt at the project working directory.
std::ofstream output("output.txt");
if (!output.is_open())
return -1;
std::cout << "file is open" << std::endl;
output << "Hello there!";
output.flush();
output.close();
project directory screenshot
I am currently trying to read in a text file for use in a project but when running in release form (running the .exe file from a command window) the file doesn't read in. But yet in debug mode it works fine. I have tried having the files in the same directory as the .exe file but it doesn't seem to find it and I don't know why?
The code:
std::cout << "Acquiring data file..." << endl;
std::cout << "Reading data file..." << endl;
ifstream tempData;
tempData.open("temp_lincolnshire_short.txt");
if (tempData.is_open()) {
std::cout << tempData.rdbuf() << endl;
}
else {
cout << "Reading failed..." << endl;
}
tempData.close();
std::cout << "Data file closed." << endl;
What I ended up using was a relative path as identified on https://stackoverflow.com/a/35910234/3795116 which ended up being:
myFile.open("../Release/frequency.dat", ios::in);
*changing myFile to whatever your variable is.
Okay guys, I've tried everything I can think of. I'm passing in a file name into this function. A little context: hash_table is an already initialized and filled vector with key pairs, and the 'value' part of the pair is a Linked List that has the field "bucket_size". When I use cout to check if these fields are actually being accessed, they are; even the debugger lists them as being filed into the output stream. I have flush() and close() in there, but it doesn't write anything to the file. Returns true, indicating no errors in the stream. Anyone have nay ideas?
string line;
std::ofstream ofs;
if(ofs.is_open())
ofs.close();
ofs.open(filename);
if (ofs.is_open())
{
cout << "File Opened" << endl;
for (double i = 0; i < hash_table.capacity(); ++i)
{
ofs << "Bucket Number " << i;
if (hash_table[i].value != NULL)
ofs << " Bucket Size: " << hash_table[i].value->bucket_size << endl;
else
ofs << " Bucket Size: 0" << endl;
ofs.flush();
}
cout << "closing file stream" << endl;
ofs.flush();
ofs.close();
if (ofs.good())
return true;
else
return false;
}
else
{
cout << "File not opened" << endl;
return false;
}
}
You're almost certainly examining the wrong file. Remember that relative paths are relative to the working directory of the process, which is not necessarily the same as where the executable lives on disk.
I compiled and ran it by the console and now it works, with no edits made. It seems my IDE doesn't like something in the code. Regardless, thank you everyone for the response.s
I'm trying to write a program to parse the first and sixteenth columns of a CSV file (converted into .txt). I have the CSV ("posts.txt") document in the folder with the executable. But, whenever I try to run the executable, my program delivers that it cannot open the file (or that "!infile.is_open()"). Mind giving me some assistance? I'm running in Xcode 3.2.3 on Mac OSX 10.8.3. The code is shows below.
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string.h>
using namespace std;
void answeredPostGrabber()
{
ifstream inFile("posts.txt");
string postNumber;
string answerNumber;
string throwAway;
if(inFile.is_open())
{
while(inFile.good())
{
getline(inFile,postNumber,',');
cout << postNumber << ",";
for(int y=1;y++;y<16)
{
getline(inFile,throwAway,',');
}
getline(inFile,answerNumber,',');
cout << answerNumber << endl;
ofstream edges;
edges.open("edges.txt",ios::app);
edges << postNumber << "," << answerNumber<< endl;
edges.close();
ofstream nodes;
nodes.open("nodes.txt",ios::app);
nodes << postNumber << "\n" << answerNumber << endl;
nodes.close();
getline(inFile,throwAway);
}
}else cout << "ERROR: Unable to open file." << endl;
}
int main ()
{
answeredPostGrabber();
return 0;
}
Thank you in advance!
I have the CSV ("posts.txt") document in the folder with the executable.
The file should be present in the current working directory of your process, which may or may not be the same directory where the executable lives. If in doubt, try specifying the full path in ifstream inFile(...); to see whether that changes things.
Additionally, the file needs to have the correct permissions to ensure that it's readable by the process.
For some reason, Xcode will not take input from a file, while Visual C++ will.
When I run this program in xcode, the variables numberRows and numberCols stay 0 (they are initialized to 0 in the main function).
When I run it in Visual C++ they become 30 and 30 (the top line of maze.txt is "30 30" without the quotes).
Any ideas why this is happening?
void readIn(int &numberRows, int &numberCols, char maze[][100]){
ifstream inData;
inData.open("maze.txt");
if (!inData.is_open()) {
cout << "Could not open file. Aborting...";
return;
}
inData >> numberRows >> numberCols;
cout << numberRows << numberCols;
inData.close();
return;
}
There is something else wrong.
Unfortunately it is hard to tell.
Try flushing the output to make sure you get the error message:
void readIn(int &numberRows, int &numberCols, char maze[][100])
{
ifstream inData("maze.txt");
if (!inData) // Check for all errors.
{
cerr << "Could not open file. Aborting..." << std::endl;
}
else
{
// Check that you got here.
cerr << "File open correctly:" << std::endl;
// inData >> numberRows >> numberCols;
// cout << numberRows << numberCols;
std::string word;
while(inData >> word)
{
std::cout << "GOT:(" << word << ")\n";
}
if (!inData) // Check for all errors.
{
cerr << "Something went wrong" << std::endl;
}
}
}
interesting, so I followed the following suggestion from this post http://forums.macrumors.com/showthread.php?t=796818:
Under Xcode 3.2 when creating a new
project based on stdc++ project
template the target build settings for
Debug configuration adds preprocessor
macros which are incompatible with
gcc-4.2:
_GLIBCXX_DEBUG=1
_GLIBXX_DEBUG_PEDANTIC=1
Destroy them if you want Debug/gcc-4.2
to execute correctly.