爲什麼我使用「我」作爲我的數組索引後得到1？

Question

我製作了一個名爲Car的類，該類應該類似於一輛真實汽車的一些功能。我試圖讓最重的汽車和最小的汽車發動機的號碼。

正如我在下面的代碼所示，你可以看到我已經使用索引進行驗證，然後將其與「i」進行比較。但是，無論輸入什麼號碼，在兩次驗證中都會得到「1」。

什麼可能是錯的？我應該得到汽車的數量而不是「1」。

這是我代碼來獲得最重的車：

int weight = x[i].getweight(); 
if(weight > max) { 
    maxweight = weight; 
    maxIndex = i; 
} 

我車類：

public class Car 
{ 
    private String color; 
    private int weight; 
    private int state; 
    private int fuel; 
    private int Maxspeed ; 
    private int engine; 

    public Car() { 
     this.color = "White"; 
     this.weight = 1000; 
     this.state = 0; 
     this.fuel =0; 
     this.Maxspeed = 0; 
     this.engine = 0; 
    } 

    public Car (String color, int weight, 
      int state, int fuel, int Maxspeed 
      ) { 
     this.color = color; 
     this.weight = weight; 
     this.state = state; 
     this.fuel = fuel; 
     this.Maxspeed = Maxspeed; 
    } 

    public String getColor() { return this.color; } 

    public int getweight() { return this.weight; } 

    public int getstate() { return this.state; } 

    public int getfuel() { return this.fuel; } 

    public int getMaxspeed() { return this.Maxspeed; } 

    public int getengine() { return this.engine; } 


    public void setColor(String color){ 
     this.color = color; 
    } 

    public void setweight(int weight){ 
     this.weight = weight; 
    } 

    public void setstate(int state){ 
     this.state = state; 
    } 

    public void setfuel(int fuel){ 
     this.fuel = fuel; 
    } 

    public void setMaxspeed(int Maxspeed){ 
     this.Maxspeed = Maxspeed; 
    } 

    public void setengine(int engine){ 
     this.engine = engine; 
    } 

    public void showdata() { 
     System.out.println("\nCar's color is: " + this.getColor()); 
     System.out.println("Car's weight is: " + this.getweight()); 
     System.out.println("State: " + this.getstate()); 
     System.out.println("Fuel: " + this.getfuel()); 
     System.out.println("Max speed: " + this.getMaxspeed()); 
    } 

    public void accelerate(int speed){ 
     if(this.getstate() == 0 || this.getstate() == 3 || 
      this.getstate() == 4 || this.getMaxspeed() < speed) 
     { 
      System.out.println("\nCar cannot accelerate..."); 
     } 
     else { 
      System.out.println("\nCar is accelerating..."); 
      this.setfuel(this.getfuel()-2); 
      this.setstate(2); 
      if(this.getfuel() <= 0) { 
       this.setstate(4); 
      } 
     } 
    } 

    public void crash() { 
     this.setstate(3); 
     System.out.println("\nCrash!!!"); 
    } 
    public void stop() { 
     this.setstate(1); 
     System.out.println("\nCar has stopped."); 
    } 

    public void addfuel(int fuel) { 
     if(this.getstate() == 0 || this.getstate() == 4){ 
      this.setfuel(this.getfuel()+ fuel); 
     } 
     else { 
      System.out.println("You can't add fuel."); 
     } 
    } 

    public void repair() { 
     if(this.getstate() == 3){ 
      this.setstate(1); 
      System.out.println("The car has been repaired"); 
     } 
     else{ 
      System.out.println("The car is not broken"); 
     } 
    } 
} 

我主要：

import java.util.Scanner; 
public class aaa { 
    public static void main (String args []) {  
     Car x[] = new Car[2]; 
     int keep=1; 
     int counter = 0; 
     int counter_stopped = 0; 
     int max = Integer.MIN_VALUE; 
     int min = Integer.MAX_VALUE; 
     int maxIndex = 0; 
     int maxweight = 0; 
     int index_engine = 0; 
     int min_engine = 0; 

     Scanner input = new Scanner(System.in); 

     for(int i = 0; i < x.length; i++) { 
      String color; 
      int weight; 
      int fuel; 
      int Maxspeed; 
      int engine; 

      x[i] = new Car(); 

      System.out.print("\nEnter car color " + (i + 1) + ": "); 
      color = input.next(); 

      System.out.print("Enter car weight " + (i + 1) + ": "); 
      weight = input.nextInt(); 

      System.out.print("Enter car fuel " + (i + 1) + ": "); 
      fuel = input.nextInt(); 

      System.out.print("Enter car max speed " + (i + 1) + ": "); 
      Maxspeed = input.nextInt(); 

      System.out.print("Enter car engine weight " + (i + 1) + ": "); 
      engine = input.nextInt(); 


      x[i].setColor(color); 
      x[i].setweight(weight); 
      x[i].getstate(); 
      x[i].setfuel(fuel); 
      x[i].setMaxspeed(Maxspeed); 
      x[i].setengine(engine); 
     }   

     for(int i = 0; i < x.length; i++) { 
      int state; 

      System.out.print("\nEnter car state " + (i + 1) + ": "); 
      state = input.nextInt(); 
      x[i].setstate(state); 

      while(state > 4 || state < 0){ 
       System.out.print("state not valid.\nTry again: "); 
       state = input.nextInt(); 
       x[i].setstate(state); 
      } 

      do { 
       keep = menu(); 

       switch(keep) { 
       case 1: 
        accelerate(x[i]); 
        break; 

       case 2: 
        stop(x[i]); 
        break; 

       case 3: 
        crash(x[i]); 
        break; 

       case 4: 
        addfuel(x[i]); 
        break; 

       case 5: 
        repair(x[i]); 
        break;  

       case 6: 
        x[i].showdata(); 
       } 
      } while(keep != 7); 

      if(x[i].getstate() == 4 || x[i].getfuel() <= 0){ 
       counter += 1; 
      } 

      if(x[i].getstate() == 1){ 
       counter_stopped += 1; 
      } 

      int weight = x[i].getweight(); 
      if(weight > max){ 
       maxweight = weight; 
       maxIndex = i; 
      } 

      int weightengine = x[i].getengine(); 
      if(weightengine < min){ 
       min_engine = weightengine; 
       index_engine = i; 
      } 
     } 

     System.out.println("\nSUMMARY"); 
     System.out.println("Amount of cars with no fuel: " + counter); 
     System.out.println("Amount of stopped cars: " + counter_stopped); 
     System.out.println("Heaviest car: " + maxIndex); 
     System.out.println("Car with the smallest engine: " + index_engine); 
     System.out.println("============================================="); 
    } 

    public static int menu() { 
     int option = 0; 
     Scanner s = new Scanner(System.in); 

     System.out.println("\n1. Accelerate Car "); 
     System.out.println("2. Stop Car "); 
     System.out.println("3. Crash Car "); 
     System.out.println("4. Add fuel "); 
     System.out.println("5. Repair "); 
     System.out.println("6. Show data "); 
     System.out.println("7. Exit "); 
     System.out.println("============================================="); 
     System.out.print("Choose an option : "); 
     option = s.nextInt(); 
     System.out.println("============================================="); 
     return option; 
    } 

    public static void accelerate(Car myCar){ 

     Scanner input = new Scanner(System.in); 
     int s; 

     System.out.print("Enter speed: "); 
     s = input.nextInt(); 
     myCar.accelerate(s); 
     //myCar.showdata(); 
    } 

    public static void stop(Car myCar){ 
     myCar.stop(); 
    } 

    public static void crash(Car myCar){ 
     myCar.crash(); 
    } 

    public static void addfuel(Car myCar){ 
     int fuel; 
     Scanner input = new Scanner(System.in); 
     System.out.print("Amount to add: "); 
     fuel = input.nextInt(); 
     myCar.addfuel(fuel); 
    } 

    public static void repair(Car myCar){ 
     myCar.repair(); 
    } 
} 

現在，當我編譯並測試哪個引擎或汽車更小或最重時，我會得到數字1。

Answer 1

最明顯的問題是

if(weight > max){ 
    maxweight = weight; 

您比較max和weight，但隨後seeting maxweight。另外，我建議你喜歡Math.max(int, int)和Math.min(int, int)像

max = Math.max(max, weight); 
min = Math.min(min, weight); 

編輯要存儲min和max價值的，你可以從指數1初始化max和min到0和環路x.length索引。這可能看起來像

int max = 0; 
int min = 0; 
for (int i = 1; i < x.length; i++) { 
    if (x[i].getweight() > x[max].getweight) { 
     max = i; 
    } else if (x[i].getweight() < x[min].getweight) { 
     min = i; 
    } 
}