Methode "calculate" geht jetzt

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

@@ -198,7 +198,7 @@ public class Spreadsheet {
 			result = "TODO"; // TODO
 		else if (!formula.isEmpty()) {
 			try {
-				result = "" + calculate(formula);
+				result = "" + calculate(formula); //geht nicht?
 			} catch(ArithmeticException ae) {
 				result = "exc.";
 			}
@@ -234,16 +234,75 @@ public class Spreadsheet {
 		long res = 0;
 
 		// TODO implement
+		int merker = 0;
+		int zaehler = 0;
+		int neue_zahl = 0;
 
 		// 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);
+				zaehler++;
+
+				switch (zaehler){
+					case 1:
+						try {
+							res = Integer.parseInt(s);
+						}catch (Exception ignored){
+							res = Integer.parseInt(get(s));
 						}
+						break;
+					case 2:
+						switch(s) {
+							case "+":
+								merker = 1;
+								break;
+							case "-":
+								merker = 2;
+								break;
+							case "*":
+								merker = 3;
+								break;
+							case "/":
+								merker = 4;
+								break;
+							default:
+								System.out.println("ERROR");
+								break;
+						}
+						break;
+					case 3:
+						try {
+							neue_zahl = Integer.parseInt(s);
+						}catch (Exception ignored){
+							neue_zahl = Integer.parseInt(get(s));
+						}
+						res = rechne(res, merker, neue_zahl);
+
+						zaehler = 1;
+						break;
+				}
+			}
+		}
+		return res;
 	}
 
-		return res;
+	private long rechne(long a, int merker, int b) {
+		switch(merker){
+			case 1:
+				return a + b;
+			case 2:
+				return a - b;
+			case 3:
+				return a * b;
+			case 4:
+				return a / b;
+			default:
+				System.out.println("ERROR");
+				break;
+		}
+		return 0;
 	}
 
 	// -----