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Calculator.java

/*
 * Copyright 2015, The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.testing.androidjunitrunnersample;

import static com.google.common.base.Preconditions.checkArgument;

/**
 * A simple calculator with a basic set of operations.
 */
public class Calculator {

public enum Operator {ADD, SUB, DIV, MUL}

/**
     * Addition operation
     */
    public double add(double firstOperand, double secondOperand) {
        return firstOperand + secondOperand;
    }

/**
     * Substract operation
     */
    public double sub(double firstOperand, double secondOperand) {
        return firstOperand - secondOperand;
    }

/**
     * Divide operation
     */
    public double div(double firstOperand, double secondOperand) {
        checkArgument(secondOperand != 0, "secondOperand must be != 0, you cannot divide by zero");
        return firstOperand / secondOperand;
    }

/**
     * Multiply operation
     */
    public double mul(double firstOperand, double secondOperand) {
        return firstOperand * secondOperand;
    }
}