How can you run a C++ program from a Ruby script?
Suppose that the Ruby script generates a file, called "hello.txt" and I want to run a C++ program to take the hello.txt file, work with it and write another file, called "result.txt" and the Ruby script continues to read the result.txt file.
For example, in the Linux shell I wrote g++ hello.c -c hello -o hello to receive the "result.txt" file.
Is there is a way that I can run the shell code from a Ruby program?
You can use system like other people said, however you should also check the exit value to verify the success or failure.
r = system("g++ hello.c -c hello -o hello") #=> r = true if success, nil if failed
You can use system :
system("./hello file.txt")
I find that backticks are more succinct than system.
You can trigger the C++ program by shelling out as follows:
`./hello file.txt`
Can you clarify whether you need to read results.txt from the current directory?
If so, you could use something like contents = IO::readlines './results.txt'
Related
I've created a hello world program in c++ and tried to compile it in c++ like this.
[aleksf#ic-ifi-rh8-026 cpp]$ g++ testing.cpp -o testing
I know that the testing file was created because
[aleksf#ic-ifi-rh8-026 cpp]$ ls -A
testing testing.cpp
But when I try to execute the file it can't find it.
[aleksf#ic-ifi-rh8-026 cpp]$ .\testing
bash: .testing: command not found...
I don't understand whats gone wrong as this is what I've been told works.
Linux does not use \ it uses / for directory paths. Try ./testing.
Like Russel have pointed out, you need to use forward slash: ./testing
The file you're trying to run also needs to have the executable mode bit set. You can fix that by running: chmod +x testing
I want to run a C++ program in VS Code. All I get from Google is that click on run and debug (the play button) on top right in VS Code and my program will be up and running. I don't want to do from that. I want to do it from terminal.
Example, to run:
A Python file I do: python3 fileName.py
A Flutter program: flutter run
A Java file: javac fileName.java
A Go file: go run fileName.go
Is there any command similar like this in C++?
Apologies, I know my question is a little naïve.
i guess the short answer would be :
$ g++ -o < name-you-want-to-give> source.cpp
In place of replace it by any name like myprogram, etc.
./myprogram
This mean you had to install gcc compiler beforehand.
I need to be in my project directory and then i need to run
g++ 01inputFromUser.cpp -o 01inputFromUser && "/home/aman/Desktop/arjun/cpp/"01inputFromUser
so this was what I was looking for
g++ fileName.cpp -o fileName && "/path/to/project/"fileName
I just switched to ubuntu and I wanted to setup notepad++ for CPP.
So I used the NppExec plugin to compile within notepad++,
My script was :
npp_save
g++ "$(FULL_CURRENT_PATH)" -o "$(CURRENT_DIRECTORY)\$(NAME_PART)obj"
./"$(NAME_PART)obj"
Here the "obj" I used is to just save the file with an "obj" keyword nothing else.
The last line ./"$(NAME_PART)obj" is to run the program.
But it looks not working in ubuntu, it produces this error:
NPP_SAVE: Z:\home\username\cpp\test.cpp
g++ "Z:\home\username\cpp\test.cpp" -o "Z:\home\username\cpp\testobj"
; about to start a child process: "g++ "Z:\home\username\cpp\test.cpp" -o "Z:\home\username\cpp\testobj"
CreatProcess() failed with error code 2:
File not found.
./"testobj"
; about to start a child process: "./"testobj""
CreatProcess() failed with error code 2:
File not found.
I have investigated some of what I think is the problem, so I think is the usage of / and \ in changing the directory.
I don't know how to fix that, so I can not be sure.
Any ideas? :) I am using vim btw in the same machine and it is working perfectly.
In theory it might be possible (see below), in practice it is rather convoluted and works only for simple compiles (like single file hello world type).
I would suggest you try a linux program, e.g.
an editor like
scite (same editing engine as notepad++) or
kate
or a real IDE like
kdeveloper or
qtcreator.
The problems with Notepad++ inside wine and g++ outside wine (from the linux install ) are this:
notepad++ inside wine under linux is still a windows program
NppExec can only do, what a cmd inside wine can do.
starting g++ directly inside cmd is an error due to g++ being a linux binary and not a windows binary
that is your CreatProcess() failed with error code 2, it means: you are trying to execute a linux program inside wine.
That does not work! (At least not so easy.)
Though you can start linux program inside cmd inside wine using start /unix ...
started this way, g++ wants linux paths and NppExec through its variables will provide only windows paths (whatever wine has set up as drives like Z:\home\username\src\hello.cpp)
though you can convert wine paths to linux paths via the winepath -u command.
g++ started through 'start /unix ... ' inside a cmd inside wine has no proper terminal to report errors to you
though you can start an xterm for g++ and have g++ reports its messages to the xterm
the downside is that g++ will report errors using the linux paths in the xterm, so you cannot double click on an error message an get to the corresponding filename and line.
You get the idea: its complicated not comfortable.
What worked for me for a helloword.cpp was this NppExec script:
NPP_SAVE
npp_run cmd /c start /unix /usr/bin/xterm -e "/usr/bin/winepath -u '$(FULL_CURRENT_PATH)' | xargs g++ -o /tmp/a.out && /tmp/a.out ; echo 'Press return'; read"
The second line
uses an xterm,
let winepath convert the Z:\home\... path to /home/... and
have that send to g++ for compilation using /tmp/a.out as binary
if compile is successfull, /tmp/a.out is executed
the echo and read are for keeping the xterm open so that you can read the output.
If you really want to use Notepad++ inside wine, one option might be using Gnu Make outside of wine and have NppExec run make all or make run similar to the g++ in my script example. That would work for more complicated compiles.
I am just starting to use Nitrous.IO and I can't seem to find any information on the web on how to run C++ programs you make in it. Any help on how to run a C++ app made in Nitrous would be a huge help.
All commands are to be run within the console
Step 1:
Get inside the appropriate directory using the following command:
cd ./folder/subfolder/etc.
Step 2:
Type in the following command to run a fileName.cpp program:
// This will make a separate file named 'fileName'
// within the directory you are working in.
// This can now be run in the console.
g++ -o fileName fileName.cpp
Step 3:
Type in the following command to run your program:
//The output will display in the console. Enjoy!
./fileName
ps: answer was there
Respected sirs,
My name is #nimit. I want to create a batch file and run it in a DOS prompt. The batch file will execute a C++ program I've written. The output should be stored in a single text-file. How can I do this?
The C++ program output should be stored in a particular text file.
Thanks in advance,
#nimit
You can do this:
programname > outputgoeshere.txt
To collect outputs:
programname1 >> outputgoeshere.txt
programname2 >> outputgoeshere.txt
programname3 >> outputgoeshere.txt
Shell scripting (Batch files are a form of that) is something that every programmer should know how to do. I found a really great book on it a few years ago: Unix Shell Programming by Stephen Kochan and Patrick Wood. Granted, it's Unix -- and bash is far more powerful than DOS, but the principles are the same. Windows is picking up a lot of the tools that bash offers with powershell.
For a great website that lists out all of the CMD programs, visit http:// ss64.com/nt/ . That site also lists comparable bash and powershell commands. I also like how he shows you how to implement pseudo-functions, command line parameters, and all manner of cool things in batch files: http://ss64.com/nt/syntax.html
Good luck!
The following will redirect program output (stdout) to a file (overwrite file or create it if it does not exist)
$ command-name > output.log
The following will redirect program output (stdout) to a file (append file or create it if it does not exist)
$ command-name >> output.log
$ command-name >> output.log
The following will redirect program error message to a file called error.log:
$ command-name 2> error.log
Redirecting the standard error (stderr) and stdout to file, Use the following syntax:
$ command-name &> output_error.log