package javareview;

import java.io.*;
import java.util.Scanner;
import javax.swing.JOptionPane;

/**
 *
 * @author Mayelin
 */
public class JavaReview2
{
    public static void main(String[] args) throws FileNotFoundException, IOException
    {
        /****************************/
        /*         Chapter 4        */
        /****************************/
        
        // example of a while loop
	int n = 1729;
	int sum = 0;
	int digit;

	while (n > 0) 
        {
            digit = n % 10;
            sum += digit;
            n = n / 10;
	}
        System.out.println("The sum of the digits is: " + sum);
        

        // another example of a while loop
        String input;
        int number;
        
        input = JOptionPane.showInputDialog("Enter a number in the range of 1 through 100.");
        number = Integer.parseInt(input);
        
        // validate the input
        while( number < 1 || number > 100 )
        {
            input = JOptionPane.showInputDialog("Enter a number in the range of 1 through 100.");
            number = Integer.parseInt(input);
        }
        System.out.println( number + " is a valid value.");
        
        
        // example of a do-while loop
        do
        {
            input = JOptionPane.showInputDialog("Enter a number in the range of 1 through 100.");
            number = Integer.parseInt(input);
        
        } while( number < 1 || number > 100 );
        System.out.println( number + " is a valid value.");
        
        
        // nested for loop
        System.out.println("Enter a width");
        Scanner keyboardInput = new Scanner( System.in );
        int width = keyboardInput.nextInt();
        
	String output = "";
	for (int i = 1; i <= width; i++) 
        {
            // Make triangle row
            for (int j = 1; j <= i; j++)
                output += "[]";

            output += "\n";
	}
	System.out.println(output);
        
        
        // reading and writing to files
        readFromFile();
             
        writeToFile();
        
        appendToFile();
        
        
        /****************************/
        /*         Chapter 5        */
        /****************************/
        
        // passing arguments to a method
        
        int x = 10;
        displayValue(5);                        // Pass 5 into num
        displayValue(x);                        // Pass 10 into num
        displayValue(x * 4);                    // Pass 40 into num
        displayValue(Integer.parseInt("700"));  // Pass 700 into num

        
        int myNumber = 6;
        // using the value returned by a method call
        if( isValidNumber(myNumber) )
            System.out.println("\n" + myNumber + " is a valid value.");
        else
            System.out.println("\n" + myNumber + " is an invalid value.");
        
        // hierarchical method call
        System.out.println("\nI am starting in main");
        deep();
        System.out.println("Now I am back in main");
        
        
        // passing primitive values to a method
        int numberOne = 3;
        int numberTwo = 7;
        System.out.println("\nThe sum of numbers is: " + addNumbers(numberOne, numberTwo) );
        System.out.println("The value of numberOne is " + numberOne);
        
        
        // passing an object reference to a method
        Student student = new Student("John");
        System.out.println("\nThe student name is " + student.getName());
        changeStudentName(student);
        System.out.println("The student name is " + student.getName() + "\n");
        
        
        // the arguments' data type must match the parameters' data type
        // the displayValue method expects an int value
        short s = 1;
        displayValue(s);            // Java converts short to int
        
        double d = 1.0;
        displayValue( (int)d );     // Java won't convert a double to an int unless you cast
                                    // See the "Conversion between Primitive Data Types" powerpoint slide
        
        System.exit(0);
           
    }

    
    public static void readFromFile() throws FileNotFoundException
    {
        // Open the file for reading
        // you need to change this to a path in your local machine
        File file = new File("/Users/Maye/Documents/Teaching/COP3804/Input_Output_Files/file_test.txt");
        
        // this line may throw an exception
        Scanner inputFile = new Scanner( file );
        
        // read all values from the file and print them to the console window
        while( inputFile.hasNextLine() )
        {
            System.out.println( inputFile.nextLine() );
        }
        
        inputFile.close(); 
        
    }
    
            
    public static void writeToFile() throws FileNotFoundException
    {
        // Open the file for writing
        File file = new File("/Users/Maye/Documents/Teaching/COP3804/Input_Output_Files/output.txt");
        
        // this line may throw an exception
        PrintWriter outputFile = new PrintWriter(file);
        
        outputFile.println("This");
        outputFile.println("is");
        outputFile.println("the latest");
        outputFile.println("test.");
        
        outputFile.close();
    }
    
    
    public static void appendToFile() throws IOException
    {
        // Open the file for writing
        // this line may throw an exception
        FileWriter writer = new FileWriter("/Users/Maye/Documents/Teaching/COP3804/Input_Output_Files/output.txt", true);
        PrintWriter outputFile = new PrintWriter(writer);
        
        outputFile.println("APPENDING");
        outputFile.println("This");
        outputFile.println("is");
        outputFile.println("another");
        outputFile.println("test.");
        
        outputFile.close();
    }

    
    public static void displayValue(int num)
    {
        System.out.println("The value is " + num);
    }
    
    
    public static boolean isValidNumber(int x)
    {
        if( x >= 0 && x <= 10 )
            return true;
        else
            return false;
        // the body of this method could just be written as:
        //return x >= 0 && x <= 10;
    }
    
    
    public static void deep()
    {
        System.out.println("I am now in deep");
        deeper();
        System.out.println("Now I am back in deep");
    }
    
    
    public static void deeper()
    {
        System.out.println("I am now in deeper");
    }
    
    
    public static double addNumbers(int x, int y)
    {
        double sum = x+y;
        x = 9;
        return sum;
    }
    
    
    public static void changeStudentName(Student studentObject)
    {
        studentObject.setName("Bob");
    }
    
}