system() and newlines

[Pardner]

I am trying to have my c++ app use windows console commands. I currently, my program spools a bunch of commands, then outputs to a batch file, and finally my program executes the batch file via system("mybatch.bat"). I think this is really ugly and would like to execute the windoes commands directly without the use of the batch file.

I am stuck on how on the newlines, for instance:

#include "stdafx.h"
#include <string>
#include <windows.h>

using namespace std;

int main(void)
{
	string test="echo This is a test"; //first command
	test.append("\n"); //newline
	test.append("echo This is a second test"); //second command
	system(test.c_str()); //execute both commands
	system("pause"); //pause
	return 0;
}

produces the output:

This is a test
Press any key to continue...

but I expected

This is a test
This is a second test
Press any key to continue...

How can I have multiple commands in a single character array? I have tried \n, \r, and \n\r. I would prefer not to do system(command1); system(command2);. Any thoughts?

[Skillless]

You could make a list of strings and loop through them

[Pardner]

Obviously my actual program doesn't just output to the console. It should be as generalized as possible as the number of windows commands are unknown and have a wide range (1~500). I am not sure how I would keep a list of strings.

For this simple example I could do:

#include "stdafx.h"
#include <string>
#include <windows.h>

using namespace std;


int main(void)
{
	string test[2];
	int i=0,N=0;

	test[N]="echo This is a test";
	N++;
	test[N]="echo This is a second test";
	N++;
	for(i;i<N;i++){
		system(test[i].c_str()); //execute both commands
	}
	system("pause"); //pause
	return 0;
}

and it produces the expected output. But I knew adhead of time the number of commands (2).

[Skillless]

Thats exactly what a list is for, there are lots of tutorials about lists and all kinds of classes you could use for this

http://www.yolinux.com/TUTORIALS/LinuxTutorialC++STL.html
http://www.cprogramming.com/tutorial/stl/stllist.html

[Pardner]

Hmmm... interesting. I have never used vectors or lists. Thank you very much for the links. I will read through them and give them a try.

[dserbia]

You could keep the starting approach, but the console will stop executing the commands when it encounters newlines. You can use '&' to separate them.
For example, if you have:

echo 1
echo 2

and you call it using system("...") you will get
1
But if you use
echo 1 & echo 2
you will get

1
2

[Pardner]

That works too. My actual program is written with the example's approach. Fixing the program would be as simple as replacing all my \n with &. Is there an advantage to using lists over the way I was doing it?

[Skillless]

With a list you can easily add or remove a line wherever you like

but if you dont need to do that then dserbias solution is probably the easiest way