make java communicate with a C++ program

Question

I have a C++ program which uses command line as its mean for IO. I don't know C++, nor do I have the program's source code. I want my java application to open the C++ program , give some input and gather the result from the C++ code. Is there a way?

UPDATE: I need to enter the input at runtime.

Opening the program should not be the problem. Providing input depends if the the input is read from run arguments or from stdin. Reading output depends if it is written to file or on stdout. For concrete solution, pleas provide more details. — Krever, Jan 29 '15 at 06:17

score 1 · Answer 1 · edited May 23 '17 at 11:43

1

You can use java.lang.Runtime

For example:

 public class TestRuntime {
        public static void main(String[] args) {
            try {
                Process p = Runtime.getRuntime().exec("test.bat");
                // test.bat or test.sh in linux is script with command to run (c++) program 
                //  or direct path to application's exec
                BufferedReader in = new BufferedReader(
                                    new InputStreamReader(p.getInputStream()));
                String line = null;
                while ((line = in.readLine()) != null) {
                    System.out.println(line);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

In addition, you can read about difference between Runtime and ProcessBuilder in this topic.

edited May 23 '17 at 11:43

Community

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answered Jan 29 '15 at 06:26

Vitaly

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Thanks, but I think that if you could also solve the entering the input problem, it would be better. :-) – dark32 Jan 29 '15 at 06:34
>>give some input. Pass parameters to c++ program at runtime is not the problem. Just add them as parameters in exec. Or you mean input at runtime? – Vitaly Jan 29 '15 at 06:36
yes at runtime Vitaly :) – dark32 Jan 29 '15 at 06:38
Yeh, it is good question. I need to think. – Vitaly Jan 29 '15 at 06:39
1

I think you can find the answer here: http://stackoverflow.com/questions/3643939/java-process-with-input-output-stream – Vitaly Jan 29 '15 at 06:42

make java communicate with a C++ program

1 Answers1