6 Object-oriented Programming

6.1	// Filename: Exercise1.java interface Function { public int evaluate(int arg); } class Half implements Function { public int evaluate(int arg) { return arg/2; } } public class Exercise1 { public static int[] applyFunctionToArray(int[] arrIn) { int length = arrIn.length; int[] arrOut = new int[length]; Function func = new Half(); for (int i=0; i< length; i++) arrOut[i] = func.evaluate(arrIn[i]); return arrOut; } }
6.2	// Filename: Exercise2.java interface Function { public int evaluate(int arg); } class Half implements Function { public int evaluate(int arg) { return arg/2; } } class Print implements Function { public int evaluate(int arg) { System.out.println(arg); return arg; } } public class Exercise2 { public static void main(String[] args) { // Create array with values 1 .. 10 int[] myArr = new int[10]; for (int i=0; i<10;) myArr[i] = ++i; // Create a print function Function print = new Print(); // Print array applyFunctionToArray(myArr, print); // Half values myArr = applyFunctionToArray(myArr, new Half()); // Print array again applyFunctionToArray(myArr, print); } public static int[] applyFunctionToArray(int[] arrIn, Function func) { int length = arrIn.length; int[] arrOut = new int[length]; for (int i=0; i< length; i++) arrOut[i] = func.evaluate(arrIn[i]); return arrOut; } } 1 2 3 4 5 6 7 8 9 10 0 1 1 2 2 3 3 4 4 5 Output from the program: