Can you declare an instance variable as a parameter in a constructor?

Question

Would this work?

class Cars{
    Cars(int speed, int weight)
}

I am just trying to figure out the constructor. If it is called like a method t

Answer 1

Constructors are used as a way to instantiate a new Instance of that Object. They don't have to have any instance variable inputs. Instance variables are declared so multiple methods within a particular class can utilize them.

public class Foo{
   String x;
   int y;

   Foo(){
      //instance variables are not set therefore will have default values
   }

   void init(String x, int y){
      //random method that initializes instance variables
      this.x = x;
      this.y = y;
   }

   void useInstance(){
      System.out.println(x+y);
   }
}

In the example above, the constructor didn't set the instance variables, the init() method did. This was so that useInstance() could use those variables.