带有命令行参数的intelliJ IDEA运行类

Question

I'm going through the Algorithms book by Sedgewick and I can't seem to make my IDE run their programs. The program starts but won't take the passed argument. Specifically I want it to open the tiny.txt file, which I set in Program arguments section but it's just ignored...

import edu.princeton.cs.algs4.In;
import edu.princeton.cs.algs4.StdOut;

public class Selection
{
    public static void sort(Comparable[] a)
    {  // Sort a[] into increasing order.
        int N = a.length;               // array length
        for (int i = 0; i < N; i++)
        {  // Exchange a[i] with smallest entry in a[i+1...N).
            int min = i;                 // index of minimal entr.
            for (int j = i+1; j < N; j++)
                if (less(a[j], a[min])) min = j;
            exch(a, i, min);
        } }
    // See page 245 for less(), exch(), isSorted(), and main().
    private static boolean less(Comparable v, Comparable w)
    {  return v.compareTo(w) < 0;  }

    private static void exch(Comparable[] a, int i, int j)
    {  Comparable t = a[i]; a[i] = a[j]; a[j] = t;  }

    private static void show(Comparable[] a)
    {  // Print the array, on a single line.
        for (int i = 0; i < a.length; i++)
            StdOut.print(a[i] + " ");
        StdOut.println();
    }

    public static boolean isSorted(Comparable[] a)
    {  // Test whether the array entries are in order.
        for (int i = 1; i < a.length; i++)
            if (less(a[i], a[i-1]))  return false;
        return true;
    }
    public static void main(String[ ] args)
    {  // Read strings from standard input, sort them, and print.
        String[] a = In.readStrings();
        sort(a);
        assert isSorted(a);
        show(a);
    }
}

Answer 1

You seem to want standard input redirection. Unfortunately, IntelliJ doesn't support that.

When you supply a command-line argument, all that does is that each word from the argument is passed as a string in the args argument of the main method. You can then write some code in main to open a BufferedReader on that file.

The alternative is to open a terminal window (or Command Prompt window) and type the command line java package.name.ClassName < filename.ext . The command processor or shell interprets the < character as a request to redirect standard input to the supplied file.

Answer 2

Alright this is what needs to be done if you want to use Algorithms code from within intelliJ IDEA on mac OS Sierra:

1, make sure to get and run algs4.app from their website

2, use intelliJ terminal to navigate to algorithms2/out/production/algorithms2 where the .class files reside

3, type in terminal: $ java-algs4 Selection < /Users/mistakeNot/Desktop/Java/algorithms2/tiny.txt