JetBrains Academy: Multiple constructors - Kamil-Jankowski/Learning-JAVA GitHub Wiki

JetBrains Academy: Multiple constructors

Movie:

You are given a class named Movie. Write two constructors for the class.

The first constructor should take three arguments (title, desc, year) and initialize the corresponding fields.

The second one should take only two arguments (title, year) and initialize name and year. In this case, the field desc should have a value "empty".

class Movie {
    private String title;
    private String desc;
    private int year;

    public Movie(String title, int year){
        this.title = title;
        this.desc = "empty";
        this.year = year;
    }
    
    public Movie(String title, String desc, int year){
        this.title = title;
        this.desc = desc;
        this.year = year;
    }

    public String getTitle() {
        return title;
    }

    public String getDesc() {
        return desc;
    }

    public int getYear() {
        return year;
    }
}

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Time:

Here's a class named Time with three fields: hours, minutes and seconds.

Add three constructors to the class:

• The first one takes only hoursand initializes this field;
• The second one takes hours and minutes and initializes the corresponding fields;
• The third one takes hours, minutes and seconds and initializes all fields.

class Time {

    int hours;
    int minutes;
    int seconds;

    public Time(int h){
        this.hours = h;
    }

    public Time(int h, int m){
        this(h);
        this.minutes = m;
    }

    public Time(int h, int m, int s){
        this(h, m);
        this.seconds = s;
    }
}

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Employee:

Here's a class named Employee with three fields: name, salary, address.

Add three constructors to the class:

• the first one is the no-argument constructor, it should initialize string fields with the value "unknown", the salary is 0;
• the second one takes name and salary, and then initializes the corresponding fields, the address is "unknown";
• the third one takes name, salary, address and initializes all fields.

class Employee {

    String name;
    int salary;
    String address;

    public Employee(){
        this.name = "unknown";
        this.salary = 0;
        this.address = "unknown";
    }

    public Employee(String name, int salary){
        this.name = name;
        this.salary = salary;
        this.address = "unknown";
    }

    public Employee(String name, int salary, String address){
        this.name = name;
        this.salary = salary;
        this.address = address;
    }
}

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Phone:

Below is a class named Phone. It has four fields: ownerName, countryCode, cityCode and number.

Add two constructor to the class:

• the first one takes ownerName and number and initializes the corresponding fields;
• the second one takes ownerName, countryCode, cityCode, number and initializes all fields.

class Phone {

    String ownerName;
    String countryCode;
    String cityCode;
    String number;

    public Phone(String ownerName, String number){
        this.ownerName = ownerName;
        this.number = number;
    }

    public Phone(String ownerName, String countryCode, String cityCode, String number){
        this.ownerName = ownerName;
        this.countryCode = countryCode;
        this.cityCode = cityCode;
        this.number = number;
    }
}

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