export declare type CalculatorOperator = '+' | '-' | '*' | '/';
export declare class Calculator {
    private firstOperand;
    private secondOperand;
    private operator;
    setFirstOperand(operand: number): void;
    setSecondOperand(operand: number): void;
    setCalculatorOperator(operator: CalculatorOperator): void;
    computeOutput(): number | undefined;
}