Creating the same text file over and over - c++

I need to create a program that writes a text file in the current folder, the text file always contains the same information, for example:
Hello,
This is an example of how the text file may look
some information over here
and here
and so on
So I was thinking in doing something like this:
#include <iostream>
#include <fstream>
using namespace std;
int main(){
ofstream myfile("myfile.txt");
myfile << "Hello," << endl;
myfile << "This is an example of how the text file may look" << endl;
myfile << "some information over here" << endl;
myfile << "and here" << endl;
myfile << "and so on";
myfile.close();
return 0;
}
Which works if the number of lines in my text file is small, the problem is that my text file has over 2000 lines, and I'm not willing to give the myfile << TEXT << endl; format to every line.
Is there a more effective way to create this text file?
Thanks.

If you have the problem of writing in same file, you need to use an append mode.
i.e., your file must be opened like this
ofstream myfile("ABC.txt",ios::app)

You may use Raw string in C++11:
const char* my_text =
R"(Hello,
This is an example of how the text file may look
some information over here
and here
and so on)";
int main()
{
std::ofstream myfile("myfile.txt");
myfile << my_text;
myfile.close();
return 0;
}
Live example
Alternatively, you may use some tools to create the array for you as xxd -i

If you don't care about the subtile differences between '\n' and std::endl, then you can create a static string with your text outside of your function, and then it's just :
myfile << str // Maybe << std::endl; too
If your text is really big, you can write a small script to format it, like changing every newlines with "\n", etc.

It sounds like you should really be using resource files. I won't copy and paste all of the information here, but there's a very good Q&A already on this website, over here: Embed Text File in a Resource in a native Windows Application
Alternatively, you could even stick the string in a header file then include that header file where it's needed:
(assuming no C++11 since if you do you could simply use Raw to make things a little easier but an answer for that has already been posted - no need to repeat).
#pragma once
#include <iostream>
std::string fileData =
"data line 1\r\n"
"data line 2\r\n"
"etc.\r\n"
;
Use std::wstring and prepend the strings with L if you need more complex characters.
All you need to do is to write a little script (or even just use Notepad++ if it's a one off) to replace backslashes with double backslash, replace double quotation marks with backslash double quotation marks, and replace line breaks with \r\n"{line break}{tab}". Tidy up the beginning and end, and you're done. Then just write the string to a file.

Related

Settings in c++ with file .txt

I would like to make a read and write file in c++. I would also like the information i write be a string. so then i can read that string from the file and see the value. Im gonna use this sort of like a settings file where the program can read your settings that you've used and apply them without having to reconfigure the program everytime. In small here's what i got:
int main()
{
std::string tortilla = "tacos";
std::string godast = "pizza";
std::ofstream MyFile;
MyFile.open("1.txt");
MyFile << tortilla;
MyFile.close();
std::ifstream ReadFile("1.txt");
while (std::getline(ReadFile, tortilla))
As you see the code is not done yet by far but i just want to learn this element for now. Thank you in before.
EDIT: Here i want the output of reading "tortilla" to be tacos. So the string is intact troughout
To output the content of tortilla add:
{
std::cout << "tortilla is " << tortilla << std::endl;
}
And iostream must be included for std::cout. HTH.

ofstream does not create file when running with CLion using CMake

I have this code to create a file, when I run it with CLion it prints out to the console but does not create file, how can I fix this? thanks
#include <iostream>
#include <fstream>
using namespace std;
int main() {
ofstream log_file;
log_file.open("sample23.txt");
if (log_file.is_open())
std::cout << "Open";
log_file << "stuff" << endl;
log_file.close();
return 0;
}
The file may be created into another directory (the working directory).
You can find that location (and change it if needed) as indicated here:
How do I change the working directory for my program
make sure to flush before closing because file is empty
try this out
ofstream f;
f.open( "sample.txt", ios::out );
f << flush;
f.close();
3 things here:
1.) In order to output to another file, you must make another variable like this:
ifstream someoutputfile;
someoutputfile.open("filename");
2.) you actually must make another variable to be "placeholder" of sorts that will automatically assign the first thing your file finds and assigns that to. This may depend on what datatype (int, double, string etc) your input file consists of. Instead of:
log_file << "stuff" << endl;
you can do something like this...
// if my input file is integers for instance..
int data = 0;
log_file >> data;
This can also work for if your file contains multiple data types.
ex:
// if I have two different data types...
string somebody;
int data = 0;
log_file >> data >> somebody;
3.) to output your file data to the screen, just follow a similar way as the example in #1.
someoutputfile << data << somebody << endl;
in addition, dont forget to close the data of BOTH your input and output files:
someoutputfile.close()
Hope that helps in some way :)

How to save .txt file in C++? [duplicate]

This question already has answers here:
How to append text to a text file in C++?
(5 answers)
Closed 7 years ago.
I have created a code writing stuff in a .txt file and read from it. But if I close the program and start to write again, it deletes the old text and overwrites it with the new one.
Is there a way to not overwrite existed data?
#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
void check() {
string text;
ifstream file;
file.open("test.txt");
getline(file, text);
if (text == "") {
cout << "There's no data in file" << endl;
} else {
cout << "File contains:" << endl;
cout << text << endl;
}
}
int main() {
check();
string text;
ofstream file;
file.open("test.txt");
cout << "Type some text" << endl;
getline(cin, text);
file << text;
return 0;
}
You need to open the file in 'append' mode like in the following example
#include <fstream>
int main() {
std::ofstream outfile;
outfile.open("yourfile.txt", std::ios_base::app);//std::ios_base::app
outfile << "your data";
return 0;
}
You can read here about fstream flagshttp://www.cplusplus.com/reference/fstream/fstream/open/
Keep in mind that in c++ there are several ways to open, save, and read text data to and from a file. It sounds like you opened with with a function (and its options) to always create a new file. One thing you could do is run your program and then close the program and use a text editor to open the file to verify whether the text you wrote to the file is actually there. Also take a look at the code that was provided by Evyatar. That example uses ofstream which allows options for read, write, and append. The "app" parameter tells the program to keep what is already in the file and append any new data that you add in the next run. When testing files where you are appending, be careful you don't end up with a huge file you did not intend to have so large.
In the code that you posted in your revised question, be sure to close the file in your check function and at the end of the program. It is possible to get things hung up if you don't. As a precaution, I usually close a file prior to opening it, just to be sure it is closed with no problems. This practice comes form my days programming in BASIC where it was an essential. If the program crashed, you couldn't open it again until you got it closed. Also, of course, close the file after you're done with it and before the end of the program. Then, when you open it in main, open with the append option.
Please, insert code for next time. If you open file in write mode, than is normal that every time you write to file, the content of file is changed. You need to use append mode.

Reading from a file, only reads text untill it gets to empty space

I managed to successfully read the text in a file but it only reads until it hits an empty space, for example the text: "Hi, this is a test", cout's as: "Hi,".
Removing the "," made no difference.
I think I need to add something similar to "inFil.ignore(1000,'\n');" to the following bit of code:
inFil>>text;
inFil.ignore(1000,'\n');
cout<<"The file cointains the following: "<<text<<endl;
I would prefer not to change to getline(inFil, variabel); because that would force me to redo a program that is essentially working.
Thank you for any help, this seems like a very small and easily fixed problem but I cant seem to find a solution.
std::ifstream file("file.txt");
if(!file) throw std::exception("Could not open file.txt for reading!");
std::string line;
//read until the first \n is found, essentially reading line by line unti file ends
while(std::getline(file, line))
{
//do something line by line
std::cout << "Line : " << line << "\n";
}
This will help you read the file. I don't know what you are trying to achieve since your code is not complete but the above code is commonly used to read files in c++.
You've been using formatted extraction to extract a single string, once: this means a single word.
If you want a string containing the entire file contents:
std::fstream fs("/path/to/file");
std::string all_of_the_file(
(std::istreambuf_iterator<char>(filestream)),
std::istreambuf_iterator<char>()
);

C++ - string.compare issues when output to text file is different to console output?

I'm trying to find out if two strings I have are the same, for the purpose of unit testing. The first is a predefined string, hard-coded into the program. The second is a read in from a text file with an ifstream using std::getline(), and then taken as a substring. Both values are stored as C++ strings.
When I output both of the strings to the console using cout for testing, they both appear to be identical:
ThisIsATestStringOutputtedToAFile
ThisIsATestStringOutputtedToAFile
However, the string.compare returns stating they are not equal. When outputting to a text file, the two strings appear as follows:
ThisIsATestStringOutputtedToAFile
T^#h^#i^#s^#I^#s^#A^#T^#e^#s^#t^#S^#t^#r^#i^#n^#g^#O^#u^#t^#p^#u^#t^#
t^#e^#d^#T^#o^#A^#F^#i^#l^#e
I'm guessing this is some kind of encoding problem, and if I was in my native language (good old C#), I wouldn't have too many problems. As it is I'm with C/C++ and Vi, and frankly don't really know where to go from here! I've tried looking at maybe converting to/from ansi/unicode, and also removing the odd characters, but I'm not even sure if they really exist or not..
Thanks in advance for any suggestions.
EDIT
Apologies, this is my first time posting here. The code below is how I'm going through the process:
ifstream myInput;
ofstream myOutput;
myInput.open(fileLocation.c_str());
myOutput.open("test.txt");
TEST_ASSERT(myInput.is_open() == 1);
string compare1 = "ThisIsATestStringOutputtedToAFile";
string fileBuffer;
std::getline(myInput, fileBuffer);
string compare2 = fileBuffer.substr(400,100);
cout << compare1 + "\n";
cout << compare2 + "\n";
myOutput << compare1 + "\n";
myOutput << compare2 + "\n";
cin.get();
myInput.close();
myOutput.close();
TEST_ASSERT(compare1.compare(compare2) == 0);
How did you create the content of myInput? I would guess that this file is created in two-byte encoding. You can use hex-dump to verify this theory, or use a different editor to create this file.
The simpliest way would be to launch cmd.exe and type
echo "ThisIsATestStringOutputtedToAFile" > test.txt
UPDATE:
If you cannot change the encoding of the myInput file, you can try to use wide-chars in your program. I.e. use wstring instead of string, wifstream instead of ifstream, wofstream, wcout, etc.
The following works for me and writes the text pasted below into the file. Note the '\0' character embedded into the string.
#include <iostream>
#include <fstream>
#include <sstream>
int main()
{
std::istringstream myInput("0123456789ThisIsATestStringOutputtedToAFile\x0 12ou 9 21 3r8f8 reohb jfbhv jshdbv coerbgf vibdfjchbv jdfhbv jdfhbvg jhbdfejh vbfjdsb vjdfvb jfvfdhjs jfhbsd jkefhsv gjhvbdfsjh jdsfhb vjhdfbs vjhdsfg kbhjsadlj bckslASB VBAK VKLFB VLHBFDSL VHBDFSLHVGFDJSHBVG LFS1BDV LH1BJDFLV HBDSH VBLDFSHB VGLDFKHB KAPBLKFBSV LFHBV YBlkjb dflkvb sfvbsljbv sldb fvlfs1hbd vljkh1ykcvb skdfbv nkldsbf vsgdb lkjhbsgd lkdcfb vlkbsdc xlkvbxkclbklxcbv");
std::ofstream myOutput("test.txt");
//std::ostringstream myOutput;
std::string str1 = "ThisIsATestStringOutputtedToAFile";
std::string fileBuffer;
std::getline(myInput, fileBuffer);
std::string str2 = fileBuffer.substr(10,100);
std::cout << str1 + "\n";
std::cout << str2 + "\n";
myOutput << str1 + "\n";
myOutput << str2 + "\n";
std::cout << str1.compare(str2) << '\n';
//std::cout << myOutput.str() << '\n';
return 0;
}
Output:
ThisIsATestStringOutputtedToAFile
ThisIsATestStringOutputtedToAFile
It turns out that the problem was that the file encoding of myInput was UTF-16, whereas the comparison string was UTF-8. The way to convert them with the OS limitations I had for this project (Linux, C/C++ code), was to use the iconv() functions. To keep the compatibility of the C++ strings I'd been using, I ended up saving the string to a new text file, then running iconv through the system() command.
system("iconv -f UTF-16 -t UTF-8 subStr.txt -o convertedSubStr.txt");
Reading the outputted string back in then gave me the string in the format I needed for the comparison to work properly.
NOTE
I'm aware that this is not the most efficient way to do this. I've I'd had the luxury of a Windows environment and the windows.h libraries, things would have been a lot easier. In this case though, the code was in some rarely used unit tests, and as such didn't need to be highly optimized, hence the creation, destruction and I/O operations of some text files wasn't an issue.