java內部類，float，ArrayList, HashMap程式碼範例

import java.util.ArrayList;<br />import java.util.HashMap;<br />import java.util.Map;<br />import java.util.Vector;</p><p>public class Test {<br />private static int m_iNum = 0;<br />private int mCount;</p><p>public Test() {<br />mCount = 0;<br />m_iNum = 0;<br />}</p><p>public Test(int num) {<br />mCount = 1;<br />m_iNum = num;<br />}</p><p>public static void main(String argv[])<br />{</p><p> int arr1[] = {4, 5, 2, 1, 3, 9, 0, 7, 6, 8};</p><p> System.out.println("/nmax number in arrray arr1 is:" + maxInt(arr1, arr1.length));</p><p> Test sd = new Test();</p><p> float f21 = 3; // ok<br />// float f1 = 3.4; // ERROR! Type mismatch: cannot convert from double to float<br /> float f1 = 3.4f;<br /> float f3 = 3.4f;<br /> f3 = f3 + 1;</p><p> int i = 0;<br /> ArrayList list = new ArrayList();<br /> Vector v = new Vector();<br /> while(i < 10) {<br /> list.add(i);<br /> list.add(i);<br /> v.add(i);<br /> i++;<br /> }</p><p> System.out.println("ArrayList:");<br /> for(i = 0; i < list.size(); i++) {<br /> System.out.print(list.get(i) + ", ");<br /> }</p><p> System.out.println("/nVector:");<br /> for(i = 0; i < v.size(); i++) {<br /> System.out.print(v.get(i) + ", ");<br /> }</p><p> // 一個類集不能直接儲存基礎資料型別 (Elementary Data Type)int，char，double等的值<br />// ArrayList <int> mylist1 = new ArrayList <int>();<br /> ArrayList <int[]> mylist2 = new ArrayList <int[]>();<br /> ArrayList <String> mylist3 = new ArrayList <String>();<br /> ArrayList <Integer> mylist4 = new ArrayList <Integer>();</p><p> Map<String, String> map1 = new HashMap<String, String>();<br /> Map<Integer, String> map2 = new HashMap<Integer, String>();<br /> for (int j = 0; j < 10; j++) {<br /> map2.put(j, "Hello " + j);<br /> }</p><p> System.out.println();<br /> for(int j = 0; j < map2.size(); j++) {<br /> System.out.println(map2.get(j));<br /> }<br />}</p><p>public String toString()<br />{<br />System.out.println("BBB" + this.m_iNum);</p><p>return "Z";<br />}</p><p>static void setInt(int i){<br />i++;<br />System.out.println("setInt(): i = " + i);<br />}</p><p>// 奇數在前，偶數在後<br />public int[] fun(int[] arr) {<br />int n = arr.length;<br />int i = 0;<br />int j = n - 1;</p><p>while (i < j) {<br />if (arr[i] % 2 != 0) { // odd number<br />i++;<br />} else { // even<br />if (arr[j] % 2 != 0) {<br />int temp = arr[i];<br />arr[i] = arr[j];<br />arr[j] = temp;<br />}<br />j--;<br />}<br />}</p><p>return arr;<br />}</p><p>public static int maxInt(int[] arr, int n){</p><p>for(int i = 1; i < n; i++)<br />{<br />arr[0] = arr[i] > arr[0] ? arr[i]:arr[0];<br />}</p><p>return arr[0];<br />}</p><p>protected class Test1 extends Test{<br />public Test1(int count) {<br />setInt(0); // 非靜態內部類可以訪問外部類的靜態和非靜態成員函數<br />toString();<br />System.out.println("mCount = " + mCount); // 非靜態內部類只能訪問外部類的非靜態成員變數<br />}<br />}</p><p>static class Test2 extends Test{<br />public Test2(int count) {<br />setInt(0); // 靜態內部類可以訪問外部類的靜態和非靜態成員函數<br />toString();<br />System.out.println("m_iNum = " + m_iNum); // 靜態內部類只能訪問外部類的靜態成員變數<br />}<br />}</p><p>}<br />