For Example, I have compiled a C++ program through Cygwin g++ on my Windows PC. It accepts (cin) two strings and parses it to return a single string.
I am thinking of using it in a batch file. Is there any way I can return the result to the .bat program directly by passing the two strings as arguments without actually executing all the input dialogues. (Something like "asd.exe -param1,param2" )
Is it to be implemented in the cpp code end. If so, give me a start where to look upon.
To write to stdin u redirect the stdin using
so
prog<"params"
will execute prog and readin String "params" from std::cin
same as redirecting stdout to file.
The other option would be to put the input parameters as arguments to main
main(argv,argc){
and read argc as the array of string arguments to the program
Related
I have this set of .gz files and inside each of them is a single text file. This text file needs to be used in a C program. The following code solves this problem somehow where parameters 1 and 2 are integers which I'm receiving as arguments for the C program (argc, argv[]) in main().
gzip -dc xyz.txt.gz | ./program parameter1 parameter2
Can someone explain how the above code works in command line?
How does the text file automatically get passed to the program?
Do I need to write extra code in the C program to receive this text file?
The shell connects the stdout of one command directly to the stdin of the other command through a pipe(7). Neither program has to do anything out of the ordinary to take advantage of this.
I have a program I am writing, I have already completed it, but the requirement/specification for it says that:
In the "Command Prompt", if someone runs your program like this:
Peter David < savednames.txt
it should print out the names inside savednames.txt that matches each of "Peter" and "David"
I have written the program but my own is interactive, i.e it asks for the file, then the name you want to search for, and then it prints the matches.
It works perfectly fine, but I don't understand what the running of the program in command prompt like this: "Peter David < savednames.txt" means. I am using C++ on Microsoft Windows.
Please I need your help to explain it and how to implement it in my code...is it some kind of operator overloading or ...I don't understand!
On the command line, < is used for input redirection. The shell opens the file whose name follows the < and copies its contents into standard input for the program.
So if you called program input.txt, you could open the file and read its contents using std::ifstream or whatever; if you called program < input.txt, you could just read the file's contents from stdin using cin.
You can also do the same for output. Instead of opening a file and writing to it in your code, write to stdout and call your program as program > output.txt.
yourprogramname Peter David < savednames.txt
means that your program will be called with Peter as first argument, David as second argument, and its standard input will be connected to a stream reading out of savednames.txt.
You just need to read standard input one row at a time, and process it according to the arguments you received.
You just need to modify the code you already have to take the names from the command line (is there a limit? Could there be three names? Or four? You need to consider that) and to read the data from standard input stream, without any need of opening a file.
What I'd like to do is have my C++ code open up Mplus (statistical program that I've downloaded on my computer) and run it. Is it possible?
You may be able to do what you want with std::system() calls like:
std::system("program -e input_commands.txt"); // Assuming it accepts some sort of command line args
std::system("program < input_commands.txt"); // Assuming it responds to stdin
It depends on the program if this approach will work.
I have a two C++ source code in which one code generates an array for the specified input while other has to use array for execution. I want to know how can I link two C++ file such that output of the first file is the input for second one ?
Since they're separate programs, that means they each have a main() function. Because of that you can't link them together. What you can do, however, is use the shell to redirect the output from one program to the input of another. For example:
program1 | program2
The above creates a so-called "pipe". What it does is feed program2 with the output of program1. Only the standard input and standard output are redirected that way. In C++ that means std::cin and std::cout. Anything printed on std::cerr or std::clog is not redirected, so make sure to never print errors, warnings or other status/informational messages on std::cout. Only print the payload data and use std::cerr or std::clog for anything else.
Linux: Compile both files and push the content of the first to the second binary with a pipe in terminal else use a socket.. you can try to ouput the data with a binary-stream and the second binary can use the same techniqe to pushs it into a array.. i hope that helps you..
I need to control a program in c++ (windows), I need to call it, then pass data to it as I collect it, finally after a certain command that program will use that data.
I need to open the prog.exe and then line by line or value by value supply it information, it works manually through cmd.
I have tried system() but this will stop after I open the program.
I need something like this.
//call it
prog.exe
//add data
DataStart
Data 1 [2 34 454 5]//etc
DataEnd //the program will take it from here.
all being passed though command line
There are different ways you could do this - if your program needs to execute part of the way through your code before getting the data as input, you can just use standard input, and prompt the user to type the data. If you want to use variable values for the input, but you will know them before execution, you can pass the information as command line arguments, where you will execute like so
prog.exe 1 2 3
and your program will access the data via argv[i] where i corresponds to each command line argument.
have your program read from standard input, and from the command line 'pipe' the result of the other program to yours
eg.
datagenerator.exe | prog.exe
assuming that datagenerator.exe writes to standard output, the | character will redirect the output to prog.exe's standard input