Add 2 constructors to the Course class. One that takes no arguments and initializes the data to all 0’s and “” (empty strings). And one constructor that takes all 4 arguments, one argument for each property and then sets the properties to these arguments that are passed in. Lastly change the main to use these new Constructors. You will not need to call the set functions any more, but do not remove the set functions from your class.

Question

Add 2 constructors to the Course class. One that takes no arguments and initializes the data to all 0’s and “” (empty strings). And one constructor that takes all 4 arguments, one argument for each property and then sets the properties to these arguments that are passed in. Lastly change the main to use these new Constructors. You will not need to call the set functions any more, but do not remove the set functions from your class.

Main Code --->

Course c1;
c1 = new Course(323, “Intro to Php”, “Intro to Php Programming”, 4);
c1.display();

Here my Code:

public class Course {

// ========================== Properties ===========================
private int courseid;
private String courseName;
private String description;
private int creditHours;

// ========================== Behaviors ==========================
public void setCourseId(int c) { courseid = c; }
public int getCourseId() { return courseid;}

public void setCourseName(String cn) { courseName = cn; }
public String getCourseName() { return courseName;}

public void setDescription(String d) { description = d; }
public String getDescription() { return description;}

public void setCreditHours(int ch) { creditHours = ch; }
public int getCreditHours() { return creditHours;}

//Returning String
public String toString() {
return courseName + ":" + description;
}

public void display() {
System.out.println("Course ID = " + getCourseId());
System.out.println("Course Name = " + getCourseName());
System.out.println("Description = " + getDescription());
System.out.println("Credit Hours = " + getCreditHours());

} //end display()

public static void main(String args []) {

Course c1;
c1 = new Course();

c1.setCourseId(109);
c1.setCourseName("Intro to Python");
c1.setDescription("This course intros the Python Prog Lang.");
c1.setCreditHours(4);

c1.display();

//Test out toString() method
System.out.println(c1);
} //end main

} //end class

Answer 1

To add the requested constructors to the Course class, you need to make the following changes:

1. Add a constructor with no arguments:
```java
public Course() {
courseid = 0;
courseName = "";
description = "";
creditHours = 0;
}
```
This constructor initializes the properties to 0 and empty strings.

2. Add a constructor with 4 arguments:
```java
public Course(int courseid, String courseName, String description, int creditHours) {
this.courseid = courseid;
this.courseName = courseName;
this.description = description;
this.creditHours = creditHours;
}
```
This constructor takes in the 4 arguments and sets the properties to these values.

Now, in the main method, you can use these new constructors as follows:

```java
Course c1 = new Course(); // uses the no-argument constructor
c1.display();

Course c2 = new Course(323, "Intro to Php", "Intro to Php Programming", 4); // uses the 4-argument constructor
c2.display();
```

With these changes, the main method no longer needs to call the set functions. However, do not remove the set functions from the class, as they may still be needed elsewhere.

Here's the updated code:

```java
public class Course {

private int courseid;
private String courseName;
private String description;
private int creditHours;

public Course() {
courseid = 0;
courseName = "";
description = "";
creditHours = 0;
}

public Course(int courseid, String courseName, String description, int creditHours) {
this.courseid = courseid;
this.courseName = courseName;
this.description = description;
this.creditHours = creditHours;
}

public void setCourseId(int c) { courseid = c; }
public int getCourseId() { return courseid;}

public void setCourseName(String cn) { courseName = cn; }
public String getCourseName() { return courseName;}

public void setDescription(String d) { description = d; }
public String getDescription() { return description;}

public void setCreditHours(int ch) { creditHours = ch; }
public int getCreditHours() { return creditHours;}

public String toString() {
return courseName + ":" + description;
}

public void display() {
System.out.println("Course ID = " + getCourseId());
System.out.println("Course Name = " + getCourseName());
System.out.println("Description = " + getDescription());
System.out.println("Credit Hours = " + getCreditHours());
}

public static void main(String args []) {

Course c1 = new Course();

c1.display();

Course c2 = new Course(323, "Intro to Php", "Intro to Php Programming", 4);
c2.display();

System.out.println(c1);
System.out.println(c2);
}
}
```