diff --git a/bin/StringCalculator.class b/bin/StringCalculator.class
index a937b0c..d2f6bcf 100644
Binary files a/bin/StringCalculator.class and b/bin/StringCalculator.class differ
diff --git a/bin/StringCalculatorTest.class b/bin/StringCalculatorTest.class
index d44b83f..a7384b5 100644
Binary files a/bin/StringCalculatorTest.class and b/bin/StringCalculatorTest.class differ
diff --git a/src/StringCalculator.java b/src/StringCalculator.java
index 487916b..723d208 100644
--- a/src/StringCalculator.java
+++ b/src/StringCalculator.java
@@ -1,9 +1,147 @@
+/*Implement a simple String calculator with a method int Add(string numbers)
+1. The method can take 0, 1 or 2 numbers, and will return their sum (for an empty string it will
+return 0) for example “” or “1” or “1,2”
+2. Add method to handle an unknown amount of numbers
+3. Add method to handle new lines between numbers (instead of commas).
+1. the following input is ok: “1\n2,3” (will equal 6)
+2. the following input is NOT ok: “1,\n”
+4. Calling Add with a negative numbers or invalid input (not numbers) will throw an
+StringCalculatorException*/
 
 public class StringCalculator {
-	public int add(String numbersStr) {
+	
+	
+	public int add(String numbersStr) throws StringCalculatorException {
 		// Returns the sum of the numbers given in numbersStr
+		String redString = numbersStr;
+		boolean empty = redString.isEmpty();
 		
-		// not yet implemented
+		if(empty) {
+			return 0;
+		}
+		
+		else if(!empty) {
+			//int x = Character.getNumericValue(element.charAt(2));
+			
+			int luku = Character.getNumericValue(redString.charAt(0));
+			return luku;
+			
+			
+			 
+		}
+		return 0;
+	
+	}
+	public int emptyString(String numbersStr0) throws StringCalculatorException {
+		String redString0 = numbersStr0;
+		boolean empty0 = redString0.isEmpty();
+		if(empty0) {
 		return 0;
+		}
+		return -1;
+	}
+	public int oneString(String numbersStr1) throws StringCalculatorException {
+		String redString1 = numbersStr1;
+		int luku = Character.getNumericValue(redString1.charAt(0));
+		return luku;
+		
+		
+	}
+	public int numberOne(String numbersStr1) throws StringCalculatorException {
+		String redString1 = numbersStr1;
+		int lenght = redString1.length();
+		boolean hadComma = redString1.contains(",");
+		if(!hadComma && (lenght >=1)) {
+			int luku = Integer.parseInt(redString1);
+			return luku;
+		}
+		else return -1;
+	}
+	
+	public int twoNumbers(String numbersStr1) throws StringCalculatorException {
+		String redString1 = numbersStr1;
+		int lenght = redString1.length();
+		boolean hadComma = redString1.contains(",");
+		if(hadComma && (lenght >=1)) {
+			int endIndex = redString1.indexOf(",");
+			String luku1 = redString1.substring(0, endIndex);
+			String luku2 = redString1.substring(endIndex+1);
+			int luku_1 = Integer.parseInt(luku1);
+			int luku_2 = Integer.parseInt(luku2);
+			int luku = luku_1 + luku_2;
+			
+			return luku;
+		}
+		else return -1;
 	}
+
+	public int twoNumbersWithN(String numbersStr1) throws StringCalculatorException {
+		String redString1 = numbersStr1;
+		int lenght = redString1.length();
+		boolean hadSlashN = redString1.contains("\n");
+		if(hadSlashN && (lenght >=1)) {
+			int endIndex = redString1.indexOf("\n");
+			String luku1 = redString1.substring(0, endIndex);
+			String luku2 = redString1.substring(endIndex+1);
+			int luku_1 = Integer.parseInt(luku1);
+			int luku_2 = Integer.parseInt(luku2);
+			int luku = luku_1 + luku_2;
+			
+			return luku;
+		}
+		else return -1;
+	}
+
+	public int numbers(String numbersStr1) throws StringCalculatorException {
+		String redString1 = numbersStr1;
+		boolean empty = redString1.isEmpty();
+			if(empty) {
+				return 0;
+			}
+		boolean hadCommaSlash = redString1.contains(",\n");
+		if(hadCommaSlash) {
+			return -1;
+		}		
+		String delims = "[,\n]";
+		String[] numbers = redString1.split(delims);
+		int lukuja = numbers.length;
+		int summa = 0;
+		for (int i = 0; i < lukuja ; i++ ) {
+			summa = summa+ Integer.parseInt(numbers[i]);
+		}
+		return summa;
+		
+			
+		}
+	public int numbersNochar(String numbersStr1) throws StringCalculatorException {
+		String redString1 = numbersStr1;
+		boolean empty = redString1.isEmpty();
+			if(empty) {
+				return 0;
+			}
+		boolean hadCommaSlash = redString1.contains(",\n");
+		if(hadCommaSlash) {
+			return -1;
+		}		
+		String delims = "[,\n]";
+		String[] numbers = redString1.split(delims);
+		
+		int lukuja = numbers.length;
+		int summa = 0;
+		
+		for (int i = 0; i < lukuja ; i++ ) {
+			char[] c = numbers[i].toCharArray();
+			int  merkkeja = c.length;
+			if(Character.isAlphabetic(c[merkkeja-1])) {
+				//do nothing
+				
+			}else if (Character.isDigit(c[merkkeja-1])) {
+			summa = summa+ Integer.parseInt(numbers[i]);
+			}
+		}
+		return summa;
+		
+			
+		}
+			
 }
diff --git a/tests/StringCalculatorTest.java b/tests/StringCalculatorTest.java
index 4ec9afe..5296beb 100644
--- a/tests/StringCalculatorTest.java
+++ b/tests/StringCalculatorTest.java
@@ -5,8 +5,87 @@
 public class StringCalculatorTest {
 
 	@Test
-	public void test() {
-		fail("Not yet implemented");
+	public void testEmpty() throws StringCalculatorException {
+		StringCalculator calc = new StringCalculator();
+		
+		int result = calc.emptyString("");
+		// Assert
+		assertEquals("No empty string", 0, result);
+	}
+	@Test
+	public void testOneChar() throws StringCalculatorException {
+		StringCalculator calc = new StringCalculator();
+		
+		int result = calc.oneString("2");
+		// Assert
+		assertEquals("No empty string", 2, result);
+		
+	}
+	@Test
+	public void test2() throws StringCalculatorException {
+		StringCalculator calc = new StringCalculator();
+	
+		int result = calc.numberOne("12");
+		// Assert
+		assertEquals("No empty string", 12, result);
 	}
 
+	@Test
+	public void test3() throws StringCalculatorException {
+		StringCalculator calc = new StringCalculator();
+	
+		int result = calc.twoNumbers("12,12");
+		// Assert
+		assertEquals("No empty string", 24, result);
+	}
+	@Test
+	public void test31() throws StringCalculatorException {
+		StringCalculator calc = new StringCalculator();
+	
+		int result = calc.twoNumbers("12,");
+		// Assert
+		assertEquals("No empty string", 12, result);
+	}
+	@Test
+	public void test4() throws StringCalculatorException {
+		StringCalculator calc = new StringCalculator();
+	
+		int result = calc.twoNumbersWithN("12\n12");
+		// Assert
+		assertEquals("No empty string", 24, result);
+	}
+	@Test
+	public void test5() throws StringCalculatorException {
+		StringCalculator calc = new StringCalculator();
+	
+		int result = calc.numbers("12\n12,12,12,12\n12");
+		// Assert
+		assertEquals("No empty string", 72, result);
+	}
+
+	@Test
+	public void test6() throws StringCalculatorException {
+	StringCalculator calc = new StringCalculator();
+
+	int result = calc.numbers("8,\n");
+	// Assert
+	assertEquals("No empty string", -1, result);
+	}
+	@Test
+	public void test7() throws StringCalculatorException {
+	StringCalculator calc = new StringCalculator();
+
+	int result = calc.numbers("8,5\n");
+	// Assert
+	assertEquals("No empty string", 13, result);
+	}
+
+	@Test
+	public void test8() throws StringCalculatorException {
+	StringCalculator calc = new StringCalculator();
+
+	int result = calc.numbersNochar("8,5\n6,s,1,g");
+	// Assert
+	assertEquals("No empty string", 20, result);
+	}
 }