package enumeration; public enum Operation { ADDITION { public double anwenden(double op1, double op2) { return op1 + op2; } }, SUBTRAKTION { public double anwenden(double op1, double op2) { return op1 - op2; } }, MULTIPLIKATION { public double anwenden(double op1, double op2) { return op1 * op2; } }; public abstract double anwenden(double op1, double op2); }