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Abhishek Ramchandran
1,063 Pointshow to add a constructor with a string parameter
I have the task of adding a second constructor with a String parameter. I thought I had it right but the program thinks otherwise. Can you tell me what I have missed?
public class Spaceship {
public String mType;
public Spaceship () {
mType = "SHUTTLE";
}
public setSpaceship (String typeOfShip) {
mType = typeOfShip;
}
public String getType() {
return mType;
}
public void setType(String type) {
mType = type;
}
}
2 Answers
Steve Hunter
57,712 PointsHi there,
In short, I think it is just a convention that works across multiple languages. It makes for clearer code and demands consistency in the creation of objects. It would help in examples of inheritance also making the code clear.
Java will create a default constructor for a class if you don't declare one explicitly. Java won't know you've done that unless you adhere to the convention. So, if you don't then the constructor won't get called at the point of instantiating an instance of the classas Java will use its own default constructor. Without this convention, the compiler won't know which method is a constructor and which are just instance methods so there needs to be a way of clearly defining that.
Make sense?
Steve.
Steve Hunter
57,712 PointsHi there,
You're pretty close. Both methods are constructors. One is a default one, which takes no parameters - you've done that correctly. Next, you want a constructor that takes a string parameter. Constructors are called the name of the class so the two constructors togetherwould look like:
public Spaceship(){
mType = "SHUTTLE";
}
public Spaceship(String type){
mType= type;
}
Steve.
Abhishek Ramchandran
1,063 PointsYup, gotcha. Thanks a bunch, could you briefly explain the logic for why constructors are the name of the class itself? Appreciate it!
Abhishek Ramchandran
1,063 PointsAbhishek Ramchandran
1,063 PointsYes, that was immensely helpful. Thanks so much!