Question

我创建了一个对象数组，有5个不同的数组，主要包含整数和字符串（人名和车辆类型）。我的问题是，一旦我创建了一个对象数组，如何显示与所选索引相关的信息？

class Vehicle
{
    int passengers, fuelCapacity, mpg;
    String type, name;

    Vehicle(String n, String t, int p, int f, int m)
    {
        passengers = p;
        fuelCapacity = f;
        mpg = m;
        type = t;
        name = n;
    }

    int range()
    {
        return mpg * fuelCapacity;
    }

}

// Declaring Vehicles array for the pertinent information.
Vehicle[] iVehicles = new Vehicle[10];

// array consisting of the types of vehicles.
String[] types = {"Truck", "Sportscar", "SUV", "Sedan", "Coupe", "Truck","Truck", "Sportscar", "SUV", "Sedan"};

// array consisting of the number of passengers per vehicle.
int[] nmbrOfPassengers = {2,2,8,4,4,4,2,2,7,4};

// array consisting of each vehicles fuel capacity in gallons.
int[] fuelCapacity = {15,15,20,20,12,15,19,19,16,10};

//array consisting of integers containing each vehicles miles per gallon.
int[] milesPerGallon = {20,18,13,35,31,34,39,19,22,25};


// array consisting of the names
String[] aNames = { "brian","bob","fred","janet","claire","bill","rudy","sandy","samuel","joan"};

for (int i = 0; i < iVehicles.length; i++)
{
    iVehicles[i] = new Vehicle(aNames[i], types[i], nmbrOfPassengers[i], fuelCapacity[i], milesPerGallon[i]);
}

// This is the portion i'm stumped on.
System.out.print(iVehicles[1]);

Answer 1

为了显示与所选索引有关的信息，代码为：

System.out.println(iVehicles[index])

但是，System.out.println会自动调用类Vehicle的toString方法。除非您覆盖它，否则默认实现（继承自Object类）对用户来说是无用的。因此，为了显示信息，您应该提供此方法的自定义实现，在该方法中，您可以在String中连接，以及要显示的Vehicle属性中的值。

Answer 2

您可以这样打印：

System.out.print(iVehicles[1].passengers);
System.out.print(iVehicles[1].fuelCapacity);
System.out.print(iVehicles[1].mpg);
System.out.print(iVehicles[1].type);
System.out.print(iVehicles[1].name);

或

您的class Vehicle覆盖toString()方法

：

public String toString() { 
    return ("Passengers: " + this.passengers); // Concatenate all other fields.
}

现在System.out.println(iVehicles[1])将打印toString()返回的内容。

从填充了不同数据类型的数组的对象数组中读取信息

2 个答案: