Homework#2 Calculator

gistfile1.java

public class calculator(){
	private Keyboard keyboard;
	private Screen screen;
	private Stack operant;
	private Stack operator;
	private String showValue;
	private State calState;

	enum State{
		on,
		off,
	}


	public static void Main(String[] args){


	}

	public calculator(){
		this.keyboard = new Keyboard();
		this.screen = new Screen();
		this.operant = new Stack();
		this.operator = new Stack();
		showValue = null;
	}
	public void onpreesedKey()
	{
		if(calState == State.on) 
		{
			Key key = keyboard.preesedKey();
			if(key.keytype == Number)
			{
				showValue = showValue+key.value;
				screen.getOutput(showValue);
			}
			else if(key.keytype == operant)
			{
				// stack of operant shouldn't have size > 2 and operator's shouldn't have size > 1
				String keyOperator = key.value;
				if(showValue != null &&operator.isEmpty()&&!operator.equals("=")&&!operator.equals("sqr"))
				{
					//Change value from String to Double and push in Stack 
					operant.push(value);
					operator.push();
					operator.push(keyOperator);
					showValue = keyOperator;
					screen.getOutput(showValue);
				}
				else if(!operator.equals("sqr"))
				{
					operant1 = operant.pop();
					Double temp = Math.sqr(operant1);
					operant.push(temp);
					showValue = temp.parseToString
					screen.getOutput(showValue);
				}
				else if(operator.equals("=")||!operator.isEmpty())
				{
					if(operator.size>operant.size) // pressed operation again and again pop previous operator and get new operator instrade.
					{
						operator.pop();
						operator.push(keyOperator);
					}
					else
					{
						Double operant2 = operant.pop();
						Double operant1 = operant.pop();
						String currentOperator = operator.pop();
						Double result = 0;
						if(currentOperator.equals("+")
						{
							result = operant2 + operant1;
							//Follow the operator
							//ex . "+" Operant
							//...
						}
						else if(currentOperator.equals("-")
						{
							result = operant2 - operant1;
							//Follow the operator
							//ex . "+" Operant
							//...
						}
						operant.push(result);
						showValue = result.parseToString;
						screen.getOutput(showValue);

						if(!operator.equals("=")){// continue pressed operator
							operator.push(keyOperator);
							showValue = keyOperator;
							screen.getOutput(showValue);

						}	
						
					}
					
				}
			else
			{
				String nameKey = key.label;
				if(nameKey == "turn_on")
				{
					operant = new Stack();
					operator = new Stack();
					value = null;
					screen.setClear();
				}
				else if(nameKey == "turn_off")
				{
					this.turnOff();
					//bye bye...
				}
				else if(nameKey == "back")
				{
					if(showValue!=null)
					{
						showValue = showValue.substring(0,showValue.lenght-1);
					}
				}

			}
		}
		private void turnOff()
		{

		}

	}

	public class Keyboard{
		private Key[];
	
		public Keyboard(){
			Key = {new Key("0","0",Key.KeyType.number),
					new Key("1","1",Key.KeyType.number),
					new Key("2","2",Key.KeyType.number),
					new Key("3","3",Key.KeyType.number),
					new Key("4","4",Key.KeyType.number),
					new Key("5","5",Key.KeyType.number),
					new Key("6","6",Key.KeyType.number),
					new Key("7","7",Key.KeyType.number),
					new Key("8","8",Key.KeyType.number),
					new Key("9","9",Key.KeyType.number),
					new Key("+","+",Key.KeyType.operator),
					new Key("-","-",Key.KeyType.operator),
					new Key("x","*",Key.KeyType.operator),
					new Key("/","/",Key.KeyType.operator),
					new Key("^","^",Key.KeyType.operator),
					new Key("=","=",Key.KeyType.operator),
					new Key("sqr",Key.KeyType.operator),
					new Key("back",Key.KeyType.command),
					new Key("turn_on",Key.KeyType.command),
					new Key("turn_off",Key.KeyType.command)
					};
		}
		public Object preesedKey()		{
			//return Key
		}	

	}
	public class Key{
		private String label;
		private String value;
		private KeyType keytype;
	
		enum KeyType
		{
			number,
			command,
			operator
		}

		public Key(String label,String value,KeyType keytype)
		{
			this.label = label;
			this.value = value;
			this.keytype = keytype;
		}
		public Key(String label,KeyType keytype)
		{
			this.label = label;
			this.keytype = keytype;
		}
	}
	public class Screen{
		private String Output;

		public Screen()
		{
			output = null;
		}
		public void getOutput(String output)
		{
			this.output = output;
		}
		public void setClear()
		{
			output = null;
		}

	}

}