public class TestArrayList
1: //TestArrayList.java
2: //Shows two ArrayList constructors (default, and one parameter)
3: //as well as several ways to display the values, and uses of
4: //the following ArrayList methods:
5: //size()
6: //add() //two versions
7: //remove()
8: //set()
9: //contains()
10: //indexOf()
11: //clear()
12: //isEmpty()
13:
14: import java.util.ArrayList;
15: import java.util.Scanner;
16:
17: public class TestArrayList
18: {
19: private static Scanner keyboard = new Scanner(System.in);
20:
21: public static void main(String[] args)
22: {
23: //Default initial capacity will be 10.
24: //ArrayList<Integer> a = new ArrayList<Integer>();
25: //Initial capacity can be specified ...
26: ArrayList<Integer> a = new ArrayList<Integer>(20);
27:
28: //Size will be 0 (not the same as capacity).
29: System.out.println("Size of new ArrayList = " + a.size());
30: System.out.print("1Press Enter to continue ... ");
31: keyboard.nextLine();
32:
33: //Add five values and check size again.
34: for (int i=1; i<=5; i++) a.add(i);
35: System.out.println("Size after adding 5 values = " + a.size());
36: System.out.print("2Press Enter to continue ... ");
37: keyboard.nextLine();
38:
39: //Display all values in three different ways ...
40: for (int i=0; i<a.size(); i++) System.out.print(a.get(i) + " ");
41: System.out.println();
42: for (Integer entry: a) System.out.print(entry + " ");
43: System.out.println();
44: for (int entry: a) System.out.print(entry + " ");
45: System.out.println();
46: System.out.print("3Press Enter to continue ... ");
47: keyboard.nextLine();
48:
49: //Insert a new value at index 2 and display again.
50: a.add(2, 555);
51: for (Integer entry: a) System.out.print(entry + " ");
52: System.out.println();
53: System.out.print("4Press Enter to continue ... ");
54: keyboard.nextLine();
55:
56: //Remove value at index 2 and display again.
57: a.remove(2);
58: for (Integer entry: a) System.out.print(entry + " ");
59: System.out.println();
60: System.out.print("5Press Enter to continue ... ");
61: keyboard.nextLine();
62:
63: //Set new value at index 2 and display again.
64: a.set(2, 555);
65: for (Integer entry: a) System.out.print(entry + " ");
66: System.out.println();
67: System.out.print("6Press Enter to continue ... ");
68: keyboard.nextLine();
69:
70: //Check if an integer value and then an arbitrary object
71: //(in this case, a string) are in the ArrayList.
72: System.out.println(a.contains(4));
73: System.out.println(a.contains(6));
74: System.out.println(a.contains("Hello, world!"));
75: System.out.print("7Press Enter to continue ... ");
76: keyboard.nextLine();
77:
78: //Find where in the ArrayList an element is located.
79: //(in this case, a string) are in the ArrayList.
80: System.out.println(a.indexOf(4));
81: System.out.println(a.indexOf(6));
82: System.out.println(a.indexOf("Hello, world!"));
83: System.out.print("8Press Enter to continue ... ");
84: keyboard.nextLine();
85:
86: //Clear the ArrayList, then check to make sure it's empty.
87: //(in this case, a string) are in the ArrayList.
88: a.clear();
89: System.out.println(a.isEmpty());
90: System.out.print("9Press Enter to continue ... ");
91: keyboard.nextLine();
92: }
93: }
94: