Test java programs that read from stdin and write to stdout

Question

I am writing some code for a programming contest in java. The input to the program is given using stdin and output is on stdout. How are you folks testing programs that work

Answer 1

EDITED: Sorry I misread your question.

Read with scanner or bufferedreader, The latter is much faster than the former.

Scanner jin = new Scanner(System.in);

BufferedReader reader = new BufferedReader(System.in);

Write to stdout with print writer. You can also print directly to Syso but this is slower.

System.out.println("Sample");
System.out.printf("%.2f",5.123);

PrintWriter out = new PrintWriter(System.out);
out.print("Sample");
out.close();