Am using OSx(Capitan)'s Xcode to code my C++ projects. I am trying Xcode to code C++ for the first time (Not that familiar with C++ also).I have a C++ project named registration, all my Cpp and Header files are inside this directory. I need to read from a file named rinput.txt and output it to a new file named routput.txt. I have tried Visual Studio and it worked perfectly fine for me. Is there anything special I need to do in Xcode? I have already put my rinput.txt in my main directory(where all my cpp and header files resides). What should I need to do to make it work? Guys any idea?
main.cpp
#include <iostream>
#include <fstream>
#include "course.h"
#include "regist.h"
using namespace std;
int main()
{
ifstream infile( "rinput.txt" );
if( !infile ) return -1;
Registration R;
infile >> R;
ofstream ofile( "routput.txt" );
ofile << R
<< "Number of courses = " << R.GetCount() << '\n'
<< "Total credits = " << R.GetCredits() << '\n';
// Declare and initialize a Course, and modify
// its credits.
Course aCourse( "MTH_3020", 'B', 2 );
aCourse.SetCredits( 5 );
cout << aCourse << endl;
return 0;
}
Related
This is not a duplicate. I'm trying to print some output to a file in a subdirectory (in this case to a file /stuff/output_1.txt) but it doesn't seem to create any new file. The code executes but no file is created, nor any subdirectory called /stuff. Here is my code:
#include <iostream>
#include <sstream>
#include <fstream>
using namespace std;
int main(void)
{
int out = 1;
stringstream fname;
fstream f;
fname << "./stuff/output" << "_" << out << ".txt";
f.open(fname.str().c_str(), ios_base::out);
f << "hello" << "\t";
f << endl;
f.close();
}
When I instead use the line
fname << "output" << "_" << out << ".txt";
It creates a file called output_1.txt in the current directory so the rest of the code clearly works. What is going wrong?
I'm on macOS so the "/" should be correct instead of the "\" used on Windows, no?
no file is created, nor any subdirectory
You are using fstream which expects the path to exist. If you are referencing a directory and it doesn't exist, then it will fail, because either you have to create the directory before you run your program, or you have to use mkdir() to create it.
You can check with f.is_open() if your stream could be opened.
f.open(fname.str().c_str(), ios_base::out);
if (f.is_open())
{
f << "hello" << "\t";
f << endl;
f.close();
}
else
std::cerr << "Unable to open " << fname;
nor any subdirectory called ./stuff
Why did you expect fstream to create subdirectories for you ? You have to do that yourself. I got the same behaviour when testing it on my machine, and the simple solution was to do a mkdir stuff. After that, the file got correctly created. But I think it's weird no runtime error is thrown. It's not good (especially for beginners) that fstream jsut silently does nothing when the subdirectory is not existing.
I'm trying to figure out how to write to a file outside the working directory. This is the code I currently have.
#include <iostream>
#include <fstream>
#include <string>
int main()
{
std::string sp{};
std::fstream ss("C:\\Users\\onion\\AppData\\Roaming\\MetaQuotes\\Terminal\\some numbers\\MQL5\\Files\\testnew.txt", std::ios::in | std::ios::out);
if (!ss.is_open()) std::cout << "Failed" << '\n';
else
{
while (ss.is_open())
{
std::getline(ss, sp);
std::cout << sp << '\n';
ss << "new data";
if (ss.eof())break;
}
}
}
I can read the file perfectly fine, but I cant write to it? Could it be that Metatrader itself is limiting my ability to write to a file or does a file have to be in the working directory to be able to write to it? or am I just doing it wrong?
I'm trying to open a simple txt.file in c++ (visual studio), but are only triggering "else".
codes.txt is together with the main file in source files and are included. This is more or less how it looks
#include <iostream>
#include <fstream>
int main()
{
std::ifstream file("codes.txt");
if (file.is_open())
{
std::cout << "success" << std::endl;
}
else
{
std::cout << "Unable to open file" << std::endl;
}
}
The txt file did not exist in the folder of the program. Runned perfectly after it was included.
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.
I'm trying to read a text file but nothing is coming out. I feel like maybe It's not linking correctly in my Visual Studio Resources folder but if I double click it - it opens fine in visual studio and it doesn't run into any problems if I test to see if it opens or if it is good. The program compiles fine right now but there's not output. Nothing prints to my command prompt. Any suggestions?
Code
#include <iostream>
#include <iomanip>
#include <fstream>
using namespace std;
int main()
{
char str[100];
ifstream test;
test.open("test.txt");
while(test.getline(str, 100, '#'))
{
cout << str << endl;
}
test.close();
return 0;
}
Text File
This is a test Textfile#Read more lines here#and here
You try to open file by name without path, this means the file shall be in current working directory of your program.
The problem is with current directory when you run your program from VS IDE. VS by default sets current working directory for runnning program to project directory $(ProjectDir). But your test file resides in resources directory. So open() function could not find it and getline() immediately fails.
Solution is simple - copy your test file to project directory. Or copy it to target directory (where your program .exe file is created, typically $(ProjectDir)\Debug or $(ProjectDir)\Release) and change working directory setting in VS IDE: Project->Properties->Debugging->Working Directory, set to $(TargetDir). In this case it will work both from IDE and command line/Windows Explorer.
Another possible solution - set correct path to file in your open() call. For testing/education purposes you could hardcode it, but actually this is not good style of software development.
Not sure if this will help but I wanted to simply open a text file for output and then read it back in. Visual Studio (2012) seems to make this difficult. My solution is demonstrated below:
#include <iostream>
#include <fstream>
using namespace std;
string getFilePath(const string& fileName) {
string path = __FILE__; //gets source code path, include file name
path = path.substr(0, 1 + path.find_last_of('\\')); //removes file name
path += fileName; //adds input file to path
path = "\\" + path;
return path;
}
void writeFile(const string& path) {
ofstream os{ path };
if (!os) cout << "file create error" << endl;
for (int i = 0; i < 15; ++i) {
os << i << endl;
}
os.close();
}
void readFile(const string& path) {
ifstream is{ path };
if (!is) cout << "file open error" << endl;
int val = -1;
while (is >> val) {
cout << val << endl;
}
is.close();
}
int main(int argc, char* argv[]) {
string path = getFilePath("file.txt");
cout << "Writing file..." << endl;
writeFile(path);
cout << "Reading file..." << endl;
readFile(path);
return 0;
}