// LOG.JAVA
package Util;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javafx.scene.Scene;
import javafx.scene.control.TextArea;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class Log {


public static void Logger(String logText) {


    try (FileWriter fw = new FileWriter("log.pdf", true)){
        fw.write(logText);
    }
    catch(IOException exc){
        System.out.println("Du er jo en idiot!");

    }

}
public static List<String> fraLog() {
    List<String> list = new ArrayList<>();
    String s = "";

    try (BufferedReader br = new BufferedReader(new FileReader("Log.pdf"))) {
        while ((s = br.readLine()) != null) {
            list.add(s + "\r\n");
        }
    } catch (IOException exc) {
        System.out.println("I/O Error: " + exc);
    }
    return list;
}
public static void abc(Stage secondStage){
TextArea logText = new TextArea();
for (String log : Log.fraLog()) {
    logText.setText(logText.getText() + log);

	StackPane secondaryLayout = new StackPane();
	secondaryLayout.getChildren().add(logText);
	Scene secondScene = new Scene(secondaryLayout, 400, 375);
	secondStage.setTitle("Log");
	secondStage.setScene(secondScene);
	secondStage.show();

}
}
}


		Button btnLog = new Button("Log");
		grid.add(btnLog, 5, 5);
		btnLog.setOnAction(new EventHandler<ActionEvent>() {
			public void handle(ActionEvent event) {
				Log.abc(new Stage());

			}
		});


Button btnClog = new Button("Clog");
		grid.add(btnClog, 5, 6);
		btnClog.setOnAction(new EventHandler<ActionEvent>() {
			@Override
			public void handle(ActionEvent e) {

				PrintWriter writer;
				try {
					writer = new PrintWriter("log.txt");
					writer.print(" ");
					writer.close();
				} catch (FileNotFoundException e1) {

					e1.printStackTrace();
				}

			}
		});


package Logic;

import java.time.LocalDateTime;

import Util.Log;

public class Maths implements Calculator {
	LocalDateTime tid = LocalDateTime.now();
		Double svar, tal1,tal2;
		String icon;


	    public double add(double a, double b) {
	        double answer = a+b;
	        svar=answer;
	        icon = "+";
	        tal1 = a; tal2 = b;
	        String tilLog =tid +": "+tal1+" "+icon+" "+tal2+" = "+svar + "\r\n";
			Log.Logger(tilLog);
	        return answer;
	    }

	    public double subtract(double a, double b) {
	        double answer = a-b;
	        tal1 = a; tal2 = b;
	        icon = "-";
	        svar=answer;
	        String tilLog =tid +": "+tal1+" "+icon+" "+tal2+" = "+svar + "\r\n";
			Log.Logger(tilLog);
	        return answer;

	    }

	    public double multiply(double a, double b) {
	        double answer = a*b;
	        tal1 = a; tal2 = b;
	        icon = "*";
	        svar=answer;
	        String tilLog = tid +": "+tal1+" "+icon+" "+tal2+" = "+svar + "\r\n";
			Log.Logger(tilLog);
	        return answer;

	    }

	    public double divide(double a, double b) {
	        double answer = a/b;
	        tal1 = a; tal2 = b;
	        icon = "/";
	        svar=answer;
	        String tilLog = tid +": "+tal1+" "+icon+" "+tal2+" = "+svar +"\r\n";
			Log.Logger(tilLog);
	        return answer;

	    }

	    public double power(double a, double b){
	        double answer =a;


	        for (int x=2; x<=b; x++){
	            answer *= a;
	        }
	        tal1 = a; tal2 = b;
	        icon = "^";
	        svar=answer;
	        String tilLog = tid +": "+tal1+" "+icon+" "+tal2+" = "+svar + "\r\n";
			Log.Logger(tilLog);
	        return answer;

	    }

		public double rod(double inputB) {
			double answer;
			answer = Math.sqrt(inputB);
	        svar=answer;
			String tilLog = tid +" "+tal1+" "+icon+" = "+svar + "\r\n";
			Log.Logger(tilLog);
	        return answer;
		}

	}