// ApplierInt.java

// ApplierInt.java uses interfaces to apply an arbitrary function to an
// in array

// IntFun is an interface declaring f as a method from int to int.

interface IntFun {
    public int f(int x); }


// Incr instantiates method f to be the increment function

class Incr implements IntFun {

   public int f(int i) { return i+1; }

} // end Incr

// Doub instantiates method f to be the doubling function

class Doub implements IntFun {

   public int f(int i) { return 2*i; }

} // end Doub



public class ApplierInt {
  
// ApplyToArray applies Q.f to the elements of A and puts the result in B.

public static void ApplyToArray(IntFun Q, int[] A, int[] B) {
     for (int i = 0; i < A.length; i++) B[i] = Q.f(A[i]); }


public static void main(String args[]) {
int A[] = new int[] { 1,2,3 };
int B[] = new int[3];
Incr Inc = new Incr();
Doub Dub = new Doub();
ApplyToArray(Inc,A,B);
System.out.println(B[0] + " " + B[1] + " " + B[2]);
ApplyToArray(Dub,A,B);
System.out.println(B[0] + " " + B[1] + " " + B[2]);
}


} // end ApplierInt