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manc
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 Posted: Tue Oct 11, 2011 1:20 am Post subject: [C++] How to Create and Save .txt file? |
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I searched and have yet to find a solid example...
All I want to do is create a new text file, write to it, and then save it to my hard drive. It never shows up, despite whatever I try.
| Code: | #include <iostream>
#include <fstream>
int main{
ofstream fout;
fout.open("C:\\fuuuuuuu.txt");
fout << "Hello World" << endl;
fout << "Tutorial : " << 37 << endl;
fout << "fputs" << endl;
fout.close();
//or this
fstream myfile("c:\\muhfilez.txt",ios::app);
myfile.open("C:\\new.txt", ios::beg);
char* toWrite = "fuckIsuck";
myfile.write(toWrite, 10);
myfile.close();
return 0;
} |
Now tell me how stupid I am and please direct me to some help if you could @_@ Links/replies appreciated
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callmenuge
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manc
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| Posted: Tue Oct 11, 2011 2:46 am Post subject: |
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| Code: | FILE* myFile = NULL;;
myFile = fopen("C:\\fileIWannaCreate.txt", "a");
fwrite("derp", 5, 0, myFile);
fclose(myFile); |
I did this, but when it calls fclose, it throws a debugging error - it says that the stream is NULL still when it reaches that point 
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atom0s
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| Posted: Tue Oct 11, 2011 6:42 am Post subject: |
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Try using ofstream with specifically passing ios::out as the second param.
| Code: |
std::ofstream outStream( "C:\\example_file.txt", std::ios::out );
if( ! outStream.is_open() || ! outStream.good() )
{
std::cout << "Failed to create and/or open the file." << std::endl;
return 0;
}
outStream << "Hello World" << std::endl;
outStream << "Tutorial: " << 37 << std::endl;
outStream << "fputs" << std::endl;
outStream.close();
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Works fine for me.
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Stylo
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| Posted: Tue Oct 11, 2011 1:18 pm Post subject: |
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| manc wrote: | | Code: | FILE* myFile = NULL;;
myFile = fopen("C:\\fileIWannaCreate.txt", "a");
fwrite("derp", 5, 0, myFile);
fclose(myFile); |
I did this, but when it calls fclose, it throws a debugging error - it says that the stream is NULL still when it reaches that point |
Try creating the file with 'wt' permissions
| Code: |
FILE *file;
file = fopen( "MyFile.txt", "wt" ); // wt stands for Write Text, rt for Read text
fputs( "Hello World", file );
fclose( file );
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If you're trying to write / read a binary file, just replace the t (text) in a b (Binary) instead.
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manc
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| Posted: Wed Oct 12, 2011 2:29 am Post subject: |
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| Wiccaan wrote: | Try using ofstream with specifically passing ios::out as the second param.
Works fine for me. |
I ran it, and "Failed to create and/or open the file." got called, so outStream.open() or outStream.good() failed..which is why Im confused
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atom0s
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| Posted: Wed Oct 12, 2011 10:04 am Post subject: |
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| manc wrote: | | Wiccaan wrote: | Try using ofstream with specifically passing ios::out as the second param.
Works fine for me. |
I ran it, and "Failed to create and/or open the file." got called, so outStream.open() or outStream.good() failed..which is why Im confused |
Odd; there isn't really a reason why it would just fail unless you have some type of anti-virus that is blocking file creation in your root system drive. (Being C:\ in this case.) Can you create files in other locations, perhaps in the same folder as the exe? Or does every call to ofstream fail?
You can call GetLastError within the fail output to see what happened to block it from being created/opened as well:
| Code: |
std::ofstream outStream( "C:\\example_file.txt", std::ios::out );
if( ! outStream.is_open() || ! outStream.good() )
{
std::cout << "Failed to create and/or open the file." << std::endl;
std::cout << "Failed reason: " << GetLastError() << std::endl;
return 0;
}
outStream << "Hello World" << std::endl;
outStream << "Tutorial: " << 37 << std::endl;
outStream << "fputs" << std::endl;
outStream.close();
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For example, if I manually create the file and set it to read-only, ofstream will fail with error code '5'. (Access violation.)
You can find a full list of error codes here:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms681381%28v=vs.85%29.aspx
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manc
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| Posted: Wed Oct 12, 2011 11:47 pm Post subject: |
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Interesting.
When I try and create it in C:\ GetLastError() returns code 5 which is this:
ERROR_ACCESS_DENIED
5 (0x5)
Access is denied.
However, I tried creating it in my Project folder.. i.e. C:\users\me\my docs\vis2010\projects\exampleProjectname\myfile.txt, and it works fine. @_@ Gonna do more testing I guess
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atom0s
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| Posted: Thu Oct 13, 2011 9:39 am Post subject: |
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Sounds like a problem with a virus scanner blocking the creation or possibly even UAC preventing it too.
Try running your application as an Administrator after you compile it again to create the file in C:\ and see if it works then. If so then you either need to disable UAC or add the proper permissions request in your projects manifest file.
The manifest should look similar to:
| Code: |
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
<v3:trustInfo xmlns:v3="urn:schemas-microsoft-com:asm.v3">
<v3:security>
<v3:requestedPrivileges>
<v3:requestedExecutionLevel level="highestAvailable"/>
</v3:requestedPrivileges>
</v3:security>
</v3:trustInfo>
</assembly>
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To request higher access. More info here if you need help embedding it:
http://msdn.microsoft.com/en-us/library/bb756929.aspx
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