/** Triangle.java
 *  Java program which, given three sides of a triangle, determines whether the triangle is
 *  equilateral, isosceles or scalene.
 *	The program checks if the lenght of the sides are valaid and form a triangle . If not it will prompt
 *  for new input.
 *
 */

import java.io.*; // java Input/Output package

public class Triangle // declares class Triangle


// fields

{ 
    static double first; 
    static double second; 
    static double third;


    public void startTest()
    
    {

	while (true)
	
	{
		if(!testSuccess())
			break;
	}
    
    }		
		
    
    public  boolean testSuccess() // begin testSuccess method
    
    {
    	InputStreamReader stdin = new InputStreamReader(System.in); // class reads characters
        BufferedReader console =  new BufferedReader(stdin); // class buffereing character streams
        
        String s1; // input string for triangle sides. 
		String s2;
		String s3;
		String c;
 
        System.out.println("Please enter side A of the triangle"); 
 
        try // prompt and input
        
        	{
        		s1 = console.readLine(); // reading a string
            	first = Double.parseDouble(s1); // parsing a double value from the string
	    		if (first > 100.0 || first <= 0) {
				System.out.println("Side A must be a positive number not greater than 100.0");
				return true;
	    	}  
        
        } 
        
        catch(IOException ioex) // exeption handling

		{
			System.out.println("Input error"); // error output if invalid data
			System.exit(1); // program terminates
		} 

			System.out.println("Please enter side B of the triangle");
			try // prompt and input
        
        { 
            s2 = console.readLine(); // reading a string
            second = Double.parseDouble(s2); // parsing a double value from the string 
	    if (second > 100.0 || second <= 0) {
		System.out.println("Side B must be a positive number not greater than 100.0");
		return true;
	    }  
        
        } 
        
        catch(IOException ioex) // exeption handling

		{
			System.out.println("Input error"); // error output if invalid data
			System.exit(1); // program terminates
		} 

		System.out.println("Please enter side C of the triangle");
		try // prompt and input
        
        { 
        	s3 = console.readLine(); // reading a string
            	third = Double.parseDouble(s3); // parsing a double value from the string 
		if (third > 100.0 || third <= 0) {
			System.out.println("Side C must be a positive number not greater than 100.0");
		return true;
	    }  
        
        } 
        
        catch(IOException ioex) // exeption handling

		{
			System.out.println("Input error"); // error output if invalid data
			System.exit(1); // program terminates
		} 
	
		if (isValidValue(first, second, third))  //if the line length is valid, then decide the type of the triangle
		compare(first, second, third);
		else
	
		{
			System.out.println("Invalid line lengths. Cannot form a triangle. Please retry.");
			return true; //	otherwise, ask for another set of inputs
		}
		
	
		while (true)
	
		{
			System.out.println("Do you wish to continue? (y/n): ");

			try // prompt and input
        
        	{ 
        		c = console.readLine(); // reading a string
			if (c.equals("y"))
				break;
			if (c.equals("n"))
				return false;
			else 
				System.out.println("enter either y for yes or n for no");	
	    	} 
		catch(IOException ioex) // exeption handling

		{ 
			System.out.println("Input error"); // error output if invalid data
			System.exit(1); // program terminates
		} 
	
		} 
	 
		return true;
    	
       	} // end method testSuccess
	
		//test whether the input line length can form a triangle
		private boolean isValidValue(double first, double second, double third)
	
		{
			//a triangle can be formed if the sum of any two of the line length is greater than the length of the third line
			if ((first + second) > third && (first + third) > second && (second + third) > first)  
			return true;
		 
			else 
			return false;
		}

    	private void compare(double first, double second, double third) 
    	
    	{
    		if (first == second && second == third) {
			System.out.println("The triangle is equilateral");
			return;
		}
		
			if (first == second || first == third || second == third) {
			System.out.println("The triangle is isosceles");
			return;
		}  
			else  
			System.out.println("The triangle is scalene");
			return;   	
     	}
    
} // end class Triangle