英文:
Can a class name be used as a datatype for an array?
问题
我尝试执行了以下代码：
public class Phonebook {
String name;
long phno;
}
public class Store {
public static void main(String args[]) {
Phonebook p[] = new Phonebook[10];
p[0].name = "vasvi";
p[0].phno = 123456;
p[1].name = "abcd";
p[2].phno = 903747;
System.out.println(p[0].name + " " + p[1].name);
}
}
执行此代码会出现 NullPointerException。我似乎不明白为什么会出现这样的异常。我已经学到了类是用户定义的数据类型。所以我真的很困惑为什么会出现这样的异常？
英文:
I tried executing the following code
public class Phonebook {
String name;
long phno;
}
public class Store {
public static void main(String args[]) {
Phonebook p[] = new Phonebook[10];
p[0].name = "vasvi";
p[0].phno = 123456;
p[1].name = "abcd";
p[2].phno = 903747;
System.out.println(p[0].name + " " + p[1].name);
}
}
This code when executed gives the NullPointerException. I don't seem to understand why. I have learnt that classes are user defined data types. So I'm really confused why such an exception would arise?
答案1
得分: 0
看起来你还没有初始化你的数组。
英文:
it looks like you have not initialized you array.
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