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March 21st, 2005, 09:29 AM

EverLearning

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variables

Hello everybody,
I am executing a shell script from C++ program. However, the script has to be called multiple times with different names (from array), so names are variable. And I am not sure how to do this. Here is a relevant part of code:

Code:

 //File1, File2, are strings, array is array of strings
 File1 = Array[0];

 for (int i = 0; i < Index; i++)
 {
		
    File2 = Array[i++];
    File_Out = File1 + File2;
    i--; //get back to original pos;
		
   system("catwav File1.wav File2.wav File_Out.wav");  
		
   File1 = File_Out;

}

Boldfaced is the line where I need help: I think there should be a $ operator somewhere...

Thanks much.

Last edited by EverLearning : March 21st, 2005 at 09:38 AM.

March 21st, 2005, 10:12 AM

guggach

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supply a buf
and sprintf in it
catwav File1.wav File2.wav File_Out.wav
before calling system

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working on Solaris[5-9], preferred languages french and C.

March 21st, 2005, 10:25 AM

EverLearning

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Quote:

Originally Posted by guggach

supply a buf and sprintf in it
catwav File1.wav File2.wav File_Out.wav before calling system

Uuummm, you mean to do smth. like char buf[] for each?

Code:

char buf1[size] = File1.c_str();
char buf2[size] = File2.cstr();
char buf_out[size] = File_Out.c_str();

//and then just this?

system ("catwav buf1.wav buf2.wav buf_out.wav");

if not, then can you explain in greater detail?

<edit> that does not seem to work </edit>

Thanks a lot.

Last edited by EverLearning : March 21st, 2005 at 11:55 AM.

March 21st, 2005, 03:53 PM

simscripts

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Can you tell me what is the exact type of File1 and File2 and File_Out?
If that are char * , then this
File_Out=File1+File2 would not work

March 21st, 2005, 05:00 PM

EverLearning

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Quote:

Originally Posted by simscripts

Can you tell me what is the exact type of File1 and File2 and File_Out?
If that are char * , then this
File_Out=File1+File2 would not work

What the script does is concatenates 2 wave files and saves it as a new wave file, i.e. last argument of the catwav (it works, I tried).
But what I need to do is create one big wave file out of an array of given names of existing wave files, for ex.
string array[size] = {"File1", "File2", "File3"}, i.e. there exist File1.wav, File2.wav, File3.wav;

I need to pass the names of the files as variables to the script: at first just first two and save it as File_Out.wav and then File1 = File_Out (just names, i.e. strings) and call the script again:
catwav File1.wav File3.wav File_Out.wav.

Only instead of using actual File1, etc. I need to use array[i].
I think the code I provided in the first post should take care of that, I just do not know how to implement variable use in shell scripts. If it were C I would not have a problem.

And yeah, I am using string type so for C++ so concatenation is done by "+".
Thanks for helping.

Last edited by EverLearning : March 21st, 2005 at 05:39 PM.

March 21st, 2005, 09:05 PM

Andrew80

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you can do this

Code:

char * filename1 = "file1.wav";
char * filename2 = "file2.wav";

char buffer[80]; 

strcat(buffer,"catwav ");
strcat(buffer,filename1);
strcat(buffer,filename2);

system(buffer)

or , just use these functions

execl
execvp

or any othe function in that family .

March 22nd, 2005, 02:59 AM

simscripts

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if you're using C++ style string variables then you could use another string variable that will hold the actual string that will go as the parameter for the system() function.

Code:

 buffer="catwav " +  File1 + " " + File2 + " " + File_Out;
 system(buffer.c_str());

March 22nd, 2005, 10:44 AM

EverLearning

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Thanks everyone for help, it works!
I did not realize that system()'s argument can be manipulated as a regular string/char array.

March 23rd, 2005, 03:02 AM

guggach

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Code:

char * filename1 = "file1.wav";
char * filename2 = "file2.wav";

char buffer[80]; 

strcat(buffer,"catwav ");
strcat(buffer,filename1);
strcat(buffer," ");
strcat(buffer,filename2);

a more elegant way:
sprintf(buffer,"catwav %s %s",filename1,filename2);

system(buffer)

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