//implemented calculate method

Axel/src/de/hs_mannheim/informatik/spreadsheet/Spreadsheet.java

@@ -373,16 +373,72 @@ public class Spreadsheet {
 		Matcher m = Pattern.compile("([A-Z][0-9]*)|[-\\+\\*/]|[0-9]*").matcher(formula);
 
 		long res = 0;
-
+		String cellName="";
+		String operand="";
+		long value=0;
+		int row;
+		int col;
+		int lock=0;
+		int cnt=0;
 		// TODO implement
 
 		// uncomment the following to see an example how the elements of a formula can be accessed
 		while (m.find()) {        // m.find() must always be used before m.group()
 			String s = m.group();
+			
+			
+			
+			
 			if (!s.isEmpty()) {
-				System.out.println(s);
+//				System.out.println(s);
+				
+				if(Character.isLetter(s.charAt(0))) {
+					cellName= s;
+					row=getRow(cellName);
+					col=getCol(cellName);
+					value= Integer.parseInt(cells[row][col].getValue());
+					lock=0;
+					
+				}else if(Character.isDigit(s.charAt(0))) {
+						 value= Integer.parseInt(s);
+						
+						 lock=0;
+				}else {
+					operand = s;
+					System.out.println(operand);
+					lock=1;
+				}
+				
+				if(cnt==0)
+					res=value;
+				
+				if(lock==0) {
+					switch(operand) {
+					
+						case "+": res+= value;
+									break;
+								
+						case "-": res-= value;
+									
+									break;
+						
+						case "*": res*= value;
+								break;
+						case "/": if(value==0) {
+									System.out.println("division by 0 is not possible");
+						}else res/= value;
+								break;
+			
+					}
+					
+				}
+								
+				}
+					
+					cnt++;
+				
 			}
-		}
+		
 
 		return res;
 	}