Update 18.3.2022

Rechner/src/Symbol.java

@@ -15,4 +15,16 @@ public class Symbol {
 	public boolean istPlus() {
 		return s == "+";
 	}
+	
+	public boolean istOperator() {
+		return istPlus() || istMal();
+	}
+	
+	public boolean istZahl() {
+		return !istOperator();
+	}
+	
+	public int getInt() {
+		return Integer.parseInt(s);
+	}
 }