Ok, I can write to the standard input of the process, and also I know how to pass the arguments to the process.
The problem is that I have to ask for three values to the user of the program. The three questions have to appear on the textEdit area of the GUI, one after another, and after each question I have to wait for the answer and get the value that the user types into the textEdit area. I know how to do that the questions appears into the textEdit area, but I don't know how to take the values after each question and put these values into the process as an input value, to add it using addArgument() to the process.
Can anybody help me?