The constructors can also have parameters. Usually the parameters are used to set the initial states of the object.
Syntax
Syntax for Java Constructor Parameters
class ClassName{
ClassName(parameterType variable,parameterType2 variable2,...){ // constructor
...
}
}
Example
In the the following demo code Rectangle class uses the parameters, w for width and h for height, from the constructors to initialize its width and height.
class Rectangle {
double width;
double height;
Rectangle(double w, double h) {
width = w;
height = h;
}
double area() {
return width * height;
}
}
public class Main {
public static void main(String args[]) {
Rectangle mybox1 = new Rectangle(10, 20);
double area;
area = mybox1.area();
System.out.println("Area is " + area);
}
}