如何在Java中调用对象？

Question

I am kind of embarrassed about this, and definitely I am just forgetting something simple.

if this is body.java

public class body{

    public static void main(String args[])
    {
        int i = 0;
     part aPart = new part(i);
     aPart.add();
    }
}

and this is part.java

public class part{

    private int i;
    public int part(int i)
    {
        this.i = i+10;
    }
    public add ()
    {
        i = i++;
        System.out.println(i);
}

Why when i run javac to compile body.java, it says unknown symbol for part?

Answer 1

because part is your constructor (you don't declare the return type as @amir said in his answer). You should do

public part(int i) {...}

as a note, Java convention is to have class names capitalized, so you should change your file to Part.java, your class declaration to "Part", and your constructor too...

EDIT -- @coolbeans answer is correct too -- if your code in the question is correct, you are missing a closing brace.

Answer 2

javac *.java吗？

Answer 3

Change your Part class like below:-

public class Part{

    private int i;
    public Part(int i)
    {
        this.i = i+10;
    }
    public void add()
    {
        i = i++;
        System.out.println(i);
    }
}

And call it this way:-

int i = 0;
Part aPart = new Part(i);
aPart.add();

Answer 4

You need to declare the constructor

public part(int i) {
   this.i = i;
}

Answer 5

And to elaborate on what hvgotcodes said, constructors do not have a return type. The constructor of a Java class is not an ordinary method. It's sole purpose is to instantiate an object of the the class which it belongs to.