class DataOnly{
int i=0;
float f=0.0f;
boolean b=true;
}public class Test{
public static void main(String[] args)
{
DataOnly x1;
System.out.println("The DataOnly member int i is:");
System.out.println("The DataOnly member float f is:"+x1.f);
System.out.println("The DataOnly member boolean is:"+x1.b);
}
}
int i=0;
float f=0.0f;
boolean b=true;
}public class Test{
public static void main(String[] args)
{
DataOnly x1;
System.out.println("The DataOnly member int i is:");
System.out.println("The DataOnly member float f is:"+x1.f);
System.out.println("The DataOnly member boolean is:"+x1.b);
}
}
x1只是DataOnly的一个实例,但他并没有初始化呀,也就是说他现在是一个Null,既然是一个Null
你用x1.f不出错才怪呢。
正确的是:DataOnly xq = new DataOnly();就可以了呀
int i=0;
float f=0.0f;
boolean b=true;
}public class Test{
public static void main(String[] args)
{
DataOnly x1=new DataOnly();
System.out.println("The DataOnly member int i is:"+x1.i);
System.out.println("The DataOnly member float f is:"+x1.f);
System.out.println("The DataOnly member boolean is:"+x1.b);
}
}
你看看吧
要new一个实例!
呵呵
难道是刚学