英文:
Create instance of object in main function
问题
以下是您要翻译的内容：
我应该调用方法 set 来改变我创建的对象的属性，但是它给了我以下错误：
PrimerPrograma.java:34: 错误: 无法从静态上下文引用非静态变量 this
我尝试的代码是：
public class PrimerPrograma{
public class Punto{
int x;
int y;
public Punto(int lax, int lay){
x=lax;
y=lay;
}
public void set(int lax, int lay){
x=lax;
y=lay;
}
public static void main(String[]args){
Punto p=new Punto(5,5);
p.set(8,8);
System.out.println(p.x+p.y);
}
}
我如何创建 Punto 类的实例，以便我可以调用它的方法？
英文:
I am supposed to call the method set to make it change the attributes of the object I created, but is giving me the following error:
PrimerPrograma.java:34: error: non-static variable this cannot be
referenced from a static context
The code that I tried is:
public class PrimerPrograma{
public class Punto{
int x;
int y;
public Punto(int lax, int lay){
x=lax;
y=lay;
}
public void set(int lax, int lay){
x=lax;
y=lay;
}
public static void main(String[]args){
Punto p=new Punto(5,5);
p.set(8,8);
System.out.println(p.x+p.y);
}
}
How do I create an instance of the Punto class, so that I can call its methods?
答案1
得分: 1
把实例化、设置和System打印调用放在你的主函数里。我建议你逐步跟随一些关于基础知识的YouTube视频。这在刚开始会对你很有帮助。
英文:
Put the instantiation, set and System print call inside your main function. I recommend follow step-by-step some youtube videos about the basic. This will help you much in the beggining.
答案2
得分: 1
来自daniweb的内容：
非静态变量只在存在对象实例时才存在。如果你有一个静态方法，它无法访问类对象中的任何变量，除非它拥有该类的实例并使用它来访问变量。对于你的内部类，如果希望主方法能够引用它，请将public更改为static。
以下是可以正常工作的代码：
public class PrimerPrograma{
public static void main(String []args){
Punto p = new Punto(5, 5);
p.set(8,8);
System.out.println(p.x+p.y);
}
public static class Punto{
int x;
int y;
public Punto(int lax, int lay) {
x = lax;
y = lay;
}
public void set(int lax, int lay){
this.x = lax;
this.y = lay;
}
}
}
我建议阅读这个讨论。
英文:
From daniweb:
> A non-static variable only exists when there is an instance of an
> object. If you have a static method, it can NOT get to any variable in
> a class object unless it has an instance of that class and uses that
> to get to the variable. For your inner class, change public to static
> if you want the main method to be able to reference it.
This code should work:
public class PrimerPrograma{
public static void main(String []args){
Punto p = new Punto(5, 5);
p.set(8,8);
System.out.println(p.x+p.y);
}
public static class Punto{
int x;
int y;
public Punto(int lax, int lay) {
x = lax;
y = lay;
}
public void set(int lax, int lay){
this.x = lax;
this.y = lay;
}
}
}
I recommend reading this discussion.
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