Using pointers as parameter in method call in Java

Question

I have the following problem:

When using a pointer as parameter in a method call I get the "error: identifier expected" error.

This is my code:

class Data {
    Person a = new Person("John");
    Person b = new Person("Mary");

    a.willHug(b);       // Gets error: <identifier> at this line
}

class Person {
    private String name;
    private Person hugs;

    Person(String n){
        this.name = n;
    }

    public void willHug(Person p) {
        hugs = p;
    }    
}

score 5 · Accepted Answer · edited May 23 '17 at 12:27

5

You shoul put this code inside of a method in order to execute it:

For instance, the main method:

class Data {

    public static void main(String args[]){
         Person a = new Person("John");
         Person b = new Person("Mary");

         a.willHug(b);       // Gets error: <identifier> at this line

    }
}

I think you should read this question of SO in order to understand better how parameters are passed in Java.

Hope it helps.

edited May 23 '17 at 12:27

Community

1
1

answered Jan 18 '13 at 16:47

Cacho Santa

6,846
6
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73

1

Thank you! I had a third class with the main method. By symply creating an object of the Data class and calling the method in the main method, the problem was solved. Thank you again :) – user1991083 Jan 18 '13 at 17:03

score 2 · Answer 2 · answered Jan 18 '13 at 16:47

You need to surround the operation on a with a method, either a class method, a main() method, or perhaps even a constructor:

class Data {
    Person a = new Person("John");
    Person b = new Person("Mary");

    public Data() {
        a.willHug(b);
    }
}

score 2 · Answer 3 · answered Jan 18 '13 at 16:48

You need to put your code in a main method:

public static void main (String[] args) {

    Person a = new Person("John");
    Person b = new Person("Mary");

    a.willHug(b);
}

Also in Java we don't call these pointers they are just variables. A variable has a reference to a particular object instance or primitive value.

score 1 · Answer 4 · answered Jan 18 '13 at 16:47

1

You are calling a method within the Data class definition? This is not correct, you either need a 'main' to do that, or place that in another method.

answered Jan 18 '13 at 16:47

Rob Goodwin

2,676
2
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47

score 1 · Answer 5 · answered Jan 18 '13 at 16:48

You are missing a method there (I introduced a method named foo()) :

class Data {
    Person a = new Person("John");
    Person b = new Person("Mary");

    public void foo() {
        a.willHug(b);       // Gets error: <identifier> at this line
    }
}

class Person {
    private String name;
    private Person hugs;

    Person(String n){
        this.name = n;
    }

    public void willHug(Person p) {
        hugs = p;
    }    
 }

score 1 · Answer 6 · answered Jan 18 '13 at 16:48

1

The problem isn't because you use a pointer (called reference in Java) but because this line:

a.willHug(b);

is outside of any method. You can have only declaration or initialization block ({}) in that place.

answered Jan 18 '13 at 16:48

Kamil

411
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Using pointers as parameter in method call in Java

6 Answers6