Java 使用另一个类的输入
现在我有三节课。火车、货车和乘客。在火车班Java 使用另一个类的输入,java,arrays,Java,Arrays,现在我有三节课。火车、货车和乘客。在火车班 public class Train { private int seatNum = 30 + (int) (Math.random() * ((40 - 30) + 1)); //Random number of seats private int wagonNum = 5 + (int) (Math.random() * ((10 - 5) + 1));//Random number of wagons
public class Train
{
private int seatNum = 30 + (int) (Math.random() * ((40 - 30) + 1)); //Random number of seats
private int wagonNum = 5 + (int) (Math.random() * ((10 - 5) + 1));//Random number of wagons
public Train()
{
PassWagon[] wagons = new PassWagon[wagonNum];//here I created an array with random wagon numbers.
for (int i = 0; i < wagonNum; i++)
{
wagons[i] = new PassWagon(seatNum); // I added PassWagon objects to that array. I need to access "seatnum" in the PassWagon class.
}
}
}
公车
{
私人int seatNum=30+(int)(Math.random()*((40-30)+1));//座位的随机数
私有int wagonNum=5+(int)(Math.random()*((10-5)+1));//货车的随机数
公共列车()
{
PassWagon[]wagons=new PassWagon[wagonNum];//在这里,我创建了一个带有随机马车号的数组。
for(int i=0;i
及
公共级旅行车
{
私人货车餐厅;
Passenger[]rowA=new Passenger[wagonseats];//我创建了2个“Passenger”数组。问题是,wagonseats变量没有任何内容。来自其他类的“seatNum”变量在构造函数中启动。
乘客[]rowB=新乘客[货车座位];
公共旅行车(内部座位)
{
这个.wagonseats=座位;
对于(int i=0;i
我想获取“seatNum”变量,并使用它来创建rowA和rowB数组。我尝试了两种方法:
- 我在PassWagon类中生成了随机数,但这次每个wagon对象将有不同数量的座位。我希望所有的wagon都有相同数量的座位
- 我在构造函数内创建了rowA和rowB数组,这次我无法在构造函数外访问rowA和rowB数组 有人有什么想法吗
rowA
和rowB
变量作为字段,但是一旦您有了参数seat
(实际上是从另一个类判断的座位数),就应该在构造函数内部初始化它们
公共级旅行车{
私人货车餐厅;
乘客[]rowA;//只需创建,不需要初始化
乘客[]rowB;
公共旅行车(内部座位){
这个.wagonseats=座位;
rowA=新乘客[货车座位];
rowB=新乘客[货车座位];
for(int i=0;i
您的问题是,当您在构造函数之前初始化它们时,wagonseats
刚刚创建,因此它包含0
。因此您正在创建一个成员为零的数组。创建后您无法更改它,因此您应该仅在拥有正确的数字时创建它
顺便说一下,如果有两行,我想wagonseats
实际上应该是seat/2
,不是吗?或者至少,数组的大小和循环的限制应该是seat/2
public class PassWagon
{
private int wagonseats ;
Passenger[] rowA = new Passenger[wagonseats]; //I created 2 "Passenger" arrays. Problem is, wagonseats variable has nothing. "seatNum" variable from other class gets initiated at Constructor.
Passenger[] rowB = new Passenger[wagonseats];
public PassWagon(int seat)
{
this.wagonseats = seat;
for (int i = 0; i < seats; i++)
{
rowA[i] = new Passenger(); //I get an out of bounds error here because this array has nothing in it.
rowB[i] = new Passenger();
}
}
public class PassWagon {
private int wagonseats ;
Passenger[] rowA; // Just create, don't initialize yet
Passenger[] rowB;
public PassWagon(int seat) {
this.wagonseats = seat;
rowA = new Passenger[wagonseats];
rowB = new Passenger[wagonseats];
for (int i = 0; i < wagonseats; i++) {
rowA[i] = new Passenger();
rowB[i] = new Passenger();
}
}
}