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javahttp-redirectstdinpiping

Command line redirection in dr. Java

I want to input a lot doubles from a text file. This has to be done using piping. Right now I have this:

public class Average
{
    public static void main(String[] args)
    {
        double sum=0.0;
        int cnt = 0;
        while (!StdIn.isEmpty())
        {
            double value=StdIn.readDouble();
            sum += value;
            cnt++;
        }
        double average=sum/cnt;
        StdOut.println("Average is " + average);
    }
}

To execute this I write following command:

$ java Average < data.txt

The problem is that it doesn't work. It asks for more input and then calculates the average of just that input. How do I get it to calculate the average of the values in data.txt?

Solution

  • The issue is that, you are using the built-in Command Prompt from Dr. Java, which does not support redirections.

    You have to use the Command Prompt program on your PC, and get to your environment according to this procedure(part 4 and 5).