What is the meaning of the output of the following code...

Question

public class MyClass {
public static void main(String[ ] args) {
Person j;
j = new Person("John");
j.setAge(20);
celebrateBirthday(j);
System.out.println(j);
}

static void celebrateBirthday(Person p) {
p.setAge(p.getAge() + 1);
}
}

public class Person {
private String name;
private int age;

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

public int getAge() {
return age;
}

public void setAge(int a) {
this.age = a;
}
}

Answer 1

thanks

Answer 2

In the line

System.out.println(j);

You are printing the actual person object rather than one of it's attributes, ie name or age.

Answer 3

I want to know what is the meaning of the program output which is coming :

Person@2a139a55

Answer 4

Patrick Maok thanks

Answer 5

Person j;
-- Declaring a new person object under the variable 'j'

j = new Person("John");
-- Calls the Person constructor with a string input 'Person (String n)' and sets the person object's class variable 'name' as "John" (the input)

j.setAge(20);
-- Calling the void (no values return) procedure 'setAge (int a)' which takes an integer value and sets the object's class variable 'age' as 20 (the input)

celebrateBirthday(j);
-- Calls a void procedure 'celebrateBirthday(Person p)' which takes a person object and calls the class' void procedure 'setAge' to increment the object's current age 'p.getAge()' by 1 '+ 1'. Essentially John will celebrate his birthday and as a result, his age 20 will go up by 1 to become 21.

System.out.println(j)
-- This will output the Person object as a unique identifier, so Person@2a139a55 is the unique identifier in memory which is the internal representation of the object.

Answer 6

Basically if you print out the object, it will always be:
ClassName@HashCode

mn121 No problem!

Answer 7

mn121 I know what you meant as I ran your program. My answer wasn't as detailed but it gave the same reason.

Answer 8

struct human {

int age;

char name[40];

};

human h1 = {19, "John"};

h1
age += 2;
Please tell the answer

Answer 9

Fill in the blanks to increase the age of the h1 variable by 2.
struct human {

int age;

char name[40];

};

struct
human h1 = {19, "John"};

h1
age += 2;
Answer plz

Answer 10

10