c++ - system() question

[BabaG]

pretty much finished getting my little app to run and have
a question about the system() command.

i'm using a command line app called nconvert to process
photos. i use a command similar to this from the command
line:

nconvert -out outformat -o name_of_processed_file name_of_original_photo

there are three variables i use in the command line
scripting i have:

outformat
name_of_processed_file
name_of_original_photo

i tried this to get system() to execute nconvert but had
a problem with the variables:

system("nconvert -o outformat -o name_of_processed_file name_of_original_photo")

i assume the quotation marks around the nconvert command
are the source of the problem.

how do i use system() with variables for the parameters
of the command line app?

thanks,
BabaG

[BabaG]

got a reply elsewhere suggesting making a big string and using
that within the system() command. just tried it and got an error.
i declared:

string nconvert_param = "nconvert -out " + outformat + " -o " + name_of_processed_file + " " + name_of_original_photo

which i can cout to the screen and prints just as it should.
compiling, however, gives an error about not being able to
convert 'std::string' to 'const char*' for the line in my code:

system( nconvert_param );

tried declaring string nconvert_param' as 'const char nconvert_param'
but that produced a different error.

what did i get wrong here?

thanks again,
BabaG

[Duthomhas]

You are closer than you think. system() takes a (char*), so turn your string into one:

system( nconvert_param.c_str() );

Hope this helps.

[BabaG]

thanks Duoas!