// IOTool.java
// 
// Author: Rahul Simha
// Summer 2017
// 
// A tool that hides the ugly details of screen and file IO
// for initial use. We'll later expose the detail.

import java.util.*;
import java.io.*;

public class IOTool {

    public static String readStringFromTerminal (String prompt)
    {
	System.out.print (prompt);
	Scanner console = new Scanner (System.in);
	String s = console.nextLine ();
	return s;
    }

    public static int readIntFromTerminal (String prompt)
    {
	System.out.print (prompt);
	Scanner console = new Scanner (System.in);
	int i = console.nextInt ();
	return i;
    }

    public static double readDoubleFromTerminal (String prompt)
    {
	System.out.print (prompt);
	Scanner console = new Scanner (System.in);
	double d = console.nextDouble ();
	return d;
    }

    public static String[] readTextFileAsStringArray (String filename)
    {
	ArrayList<String> lines = readTextFileAsStringList (filename);
	// Convert to array.
	String[] lineArray = (String[]) lines.toArray ();
	return lineArray;
    }

    public static ArrayList<String> readTextFileAsStringList (String filename)
    {
	try {
	    File f = new File (filename);
	    if (! f.exists()) {
		System.out.println ("No such file: " + filename);
		return null;
	    }
	    LineNumberReader lnr = new LineNumberReader (new FileReader(f));
	    ArrayList<String> lines = new ArrayList<String> ();
	    String line = lnr.readLine ();
	    while (line != null) {
		lines.add (line);
		line = lnr.readLine ();
	    }
	    return lines;
	}
	catch (Exception e) {
	    System.out.println (e);
	    e.printStackTrace ();
	    System.exit (0);
	}
	return null;
    }

    public static void writeTextFileFromStringArray (String filename, String[] lines)
    {
	try {
	    PrintWriter pw = new PrintWriter (new FileWriter (filename));
	    for (String s: lines) {
		pw.println (s);
	    }
	    pw.flush ();
	    pw.close ();
	}
	catch (Exception e) {
	    System.out.println (e);
	    e.printStackTrace ();
	    System.exit (0);
	}
	
    }

    public static int stringToInt (String s)
    {
	try {
	    // Remove surrounding whitepace.
	    s = s.trim ();
	    // Parse.
	    int k = Integer.parseInt (s);
	    return k;
	}
	catch (Exception e) {
	    // If the string was illegal, our action is harsh: halt.
	    System.out.println ("Illegal string for integer: " + s);
	    System.exit (0);
	    // We won't be reaching here but the compiler needs a 
	    // return to be written.
	    return -1;
	}
    }

}