獲取錯誤的輸出

Question

我是堆棧溢出的新手，並且遇到新手程序問題（因爲我是新手）。 所以我想我會剛剛到達這一點，併發布我的代碼。 從這段代碼我希望得到的氣體量作爲輸出，但沒有什麼迎接！ 感謝任何人的幫助！

/* 
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* and open the template in the editor. 
*/ 
package testergasmilage; 

/** 
* 
* @author zane 
*/ 
public class Tester { 

    /** 
    * @param args the command line arguments 
    */ 
    public static void main(String[] args) { 
    AutoMobile car = new AutoMobile(24); 
    car.fillup(20); 
    car.TakeTrip(100); 
    double Fuel_Left = car.reportFuel; 
    System.out.println(Fuel_Left); 
     // TODO code application logic here 
    } 
} 




package testergasmilage; 

/** 
* 
* @author zane 
*/ 
public class AutoMobile { 
    public double GM; // gas Milage 

    public double gallons = 0; 
    public double miles; 
    double reportFuel; 

public AutoMobile(double GM) // this is a function to declare the milage 
     { 
} 
public void fillup (double gallons) 
{ 
    gallons += gallons; 
} 
public void TakeTrip (double miles) 
{ 
    gallons = gallons - (miles/GM); 
} 
public double reportFuel() 
{ 

    double Fuel_left = gallons - (miles/GM); 
    return Fuel_left; 
} 
} 

Answer 1

你的構造函數是空的 -

public AutoMobile(double GM){ 
    this.GM = GM; 
}