public SpreadsheetCalculator()
{
ICalculator multiple = new MultipleCalculator();
ICalculator divide = new DivideCalculator();
ICalculator add = new AddCalculator();
ICalculator subtract = new SubtractCalculator();
ICalculator end = new EndCalculator();
multiple.RegisterNext(divide);
divide.RegisterNext(add);
add.RegisterNext(subtract);
subtract.RegisterNext(end);
_calculation = multiple;
}
