Question

我想记录参数的旧值并在旧参数值上添加新参数值，我该如何在java中执行此操作？

例如，如何在auto.fillUp中添加“10”，在auto.fillUp中添加“20”？

public class Main {
    public static void main(String[] args){
         OdometerReading auto = new OdometerReading(15);
         auto.fillUp(350, 10);
         auto.fillUp(450, 20);
         System.out.println("Miles per gallon: " + auto.calculateMPG());
    }
}

里程表阅读课程：

public class OdometerReading {
    public int myStartMiles;
    public int myEndMiles;
    public double myGallonsUsed;
    public int milesInterval;
    public double getMyGallonsUsedNew;

    public OdometerReading(int assignedCarMiles){
       myStartMiles = assignedCarMiles;
       System.out.println("New car odometer reading: " + myStartMiles);
    }

    public void fillUp(int milesDriven, double gallonsUsed){
        myEndMiles = milesDriven;
        myGallonsUsed = gallonsUsed;
    }

    public double calculateMPG(){
        milesInterval = myEndMiles - myStartMiles;
        double mpg = milesInterval / myGallonsUsed;
        return mpg;
    }

    public void reset(){
        myStartMiles = myEndMiles;
        myGallonsUsed = 0;
    }

}

***注意：我是Java＆amp; amp;的初学者编程一般我很抱歉，如果这可能是一个“非专业”的问题。

Answer 1

只需在方法中进行操作，状态就会保存在对象变量中，只要你有对象的引用就好了。

public void fillUp(int milesDriven, double gallonsUsed){
    myEndMiles += milesDriven;
    myGallonsUsed += gallonsUsed;
}

注意+运算符

如何记录以前的参数值并添加到新参数值？

1 个答案: