java构造方法重载问题。

Question

class BirthDate
{
private int day;
private int month;
private int year;
private double time;

public BirthDate(int d,int m,int y)
{
day=d;
month=m;
year=y;
}

public BirthDate(int d,int m,int y,int t)
{
day=d;
month=m;
year=y;
time=t;
}

public void setDay(int d)
{
day=d;
}

public void setMonth(int m)
{
month=m;
}

public void setYear(int y)
{
year=y;
}

public int getDay()
{
return day;
}

public int getMonth()
{
return month;
}

public int getYear()
{
return year;
}

public void display()
{
System.out.println(day+ "-" + month+ "-" + year);
}
public void show()
{
System.out.println(day+ "-" + month+ "-" + year+"-" +time);
}
}

public class Test{
public static void main(String[] args)
{
Test test=new Test();
int date=9;
BirthDate d1=new BirthDate(7,7,1970);
BirthDate d2=new BirthDate(1,1,2000);
BirthDate d3=new BirthDate(1,1,2000,18.00);
test.change1(date);
test.change2(d1);
test.change3(d2);
System.out.println("date="+date);
d1.display();
d2.display();
d3.show();
}

public void change1(int i)
{
i=1234;
}

public void change2(BirthDate b)
{
b=new BirthDate(22,2,2004);
}

public void change3(BirthDate b)
{
b.setDay(22);
}
}
哪里错了？有一个错误，出现在BirthDate d3=new BirthDate(1,1,2000,18.00);这里。指向new。

Answer 1

public BirthDate(int d,int m,int y,int t)
{
day=d;
month=m;
year=y;
time=t;
}
你的构造函数中是4个int型参数
而你调用时BirthDate d3=new BirthDate(1,1,2000,18.00);
传进去的最后一个参数18.00是double型的，int型要小于double，不能自动转型，所以要报错
要么修改构造方法，改成接受一个String类型的，将18.00改成“18.00”
要么改成一个接收double类型的
或者修改18.00为18

Answer 2

下面一楼的答案 正解 verygood