Question

i have several Constructor in the class

public class Date {
       ...
       public Date(first case)
       ...
       public Date(second case)
       ...
       public Date(third case)
       ...
       public String toString(){
       ...}

How to write the code in toSTring() ????

Can any one explain to me

Answer 1

What your toString returns is not decided by how many constructor you have in your class. They are used to return a String representation that you want to be printed when you print the instances of your class. You can return any field or concatenation of some fields from it.

So, if you have a Person class with some 4-5 fields including id and name and you want to print the id and name of the person separated by a colon, when you print the instanse, your toString() would look like:-

@Override
public String toString() {
    return this.id + " : " + this.name;
}

So, if you have an instance of Person class with id = 5, name = rohit, age = 23 and some email id, then when you display that instance: –

Person person = new Person(5, "rohit", "[e-mail]", 23);
System.out.println(person);

Person person2 = new Person(6);  // Don't have `name` set
System.out.println(person2);

The above statement will print: –

5 : rohit
6 :

as output.

But you can of course put a condition in your toString to check whether a field is empty or not, and you can return a message accordingly.