public class Generics {

//    public static void printArray(int[] array) {
//        String str = "[";
//        
//        // length, length(), size()
//        for (int i = 0; i < array.length; ++i) {
//            int elem = array[i];
//            
//            str = str + " " + elem;
//        }
//        str += " ]";
//        
//        System.out.println(str);
//    }
    
//    public static void printArray(int[] array) {
//        String str = "[";
//        
//        // enhanced for loop, for-each loop
//        // for each element in array (collection)
//        // for (Type var : collectionName)
//        // doesn't work (1) if index is needed
//        //              (2) if update to collection is needed
//        for (int elem : array) {
//            str = str + " " + elem;
//        }
//        str += " ]";
//        
//        System.out.println(str);
//    }
//    
//    // method overloading: same return type, same method name,
//    //                     different parameter list (type, order, length)
//    public static void printArray(boolean[] array) {
//        String str = "[";
//
//        for (boolean elem : array) {
//            str = str + " " + elem;
//        }
//        str += " ]";
//        
//        System.out.println(str);
//    }
    
    // generic version: works only for Object/class types
    //                  must use .equals to compare
    public static <E> void printArray(E[] array) {
        String str = "[";

        for (E elem : array) {
            str = str + " " + elem;
        }
        str += " ]";
        
        System.out.println(str);
    }

    // generic contains: returns true if target is found in array
    //                   works for any Object/class type data
    public static <E> boolean contains(E[] array, E target) {
        for (E elem : array) {
            if (target.equals(elem)) { // end as soon as you have an answer
                return true;
            }
        }
        
        return false;
    }
    
    
    public static void main(String[] args) {
        Integer[] a1 = { };
        Integer[] a2 = { 10 };
        Integer[] a3 = { 3, 6, 9, 12, 15 };
        
        Boolean[] b1 = { true, false, false, true };
        
        printArray(a1);
        printArray(a2);
        printArray(a3);
        
        printArray(b1);
        
        // test generic printArray
        String[] sArr1 = { "Four", "Scores", "And" };
        String[] sArr2 = { "Hello", "World", "Hi", "Bye", "Wecome" };
        
        printArray(sArr1);
        printArray(sArr2);
        
        System.out.println("is 10 in a1? " + contains(a1, 10));  // f
        System.out.println("is 10 in a2? " + contains(a2, 10));  // t
        System.out.println("is  3 in a3? "  + contains(a3, 3));  // t
        System.out.println("is 15 in a3? " + contains(a3, 15));  // t
        System.out.println("is  9 in a3? "  + contains(a3, 9));  // t
        System.out.println("is  1 in a3? "  + contains(a3, 1));  // f
        System.out.println("is 11 in a3? " + contains(a3, 11));  // f
        
        System.out.println("is Hello   in sArr2? " + contains(sArr2, "Hello"));
        System.out.println("is Welcome in sArr2? " + contains(sArr2, "Welcome"));
        System.out.println("is Hi      in sArr2? " + contains(sArr2, "Hi"));
        System.out.println("is Hey     in sArr2? " + contains(sArr2, "Hey"));
        
        String s1 = "Hello";
        String s2 = new String("Hello");
        
        System.out.println("s1 == s2      ? " + (s1 == s2));
        System.out.println("s1.equals(s2) ? " + (s1.equals(s2)));
    }
    
}