java内部类，float，ArrayList, HashMap代码示例

import java.util.ArrayList; import java.util.HashMap; import java.util.Map; import java.util.Vector; public class Test { private static int m_iNum = 0; private int mCount; public Test() { mCount = 0; m_iNum = 0; } public Test(int num) { mCount = 1; m_iNum = num; } public static void main(String argv[]) { int arr1[] = {4, 5, 2, 1, 3, 9, 0, 7, 6, 8}; System.out.println("/nmax number in arrray arr1 is:" + maxInt(arr1, arr1.length)); Test sd = new Test(); float f21 = 3; // ok // float f1 = 3.4; // ERROR! Type mismatch: cannot convert from double to float float f1 = 3.4f; float f3 = 3.4f; f3 = f3 + 1; int i = 0; ArrayList list = new ArrayList(); Vector v = new Vector(); while(i < 10) { list.add(i); list.add(i); v.add(i); i++; } System.out.println("ArrayList:"); for(i = 0; i < list.size(); i++) { System.out.print(list.get(i) + ", "); } System.out.println("/nVector:"); for(i = 0; i < v.size(); i++) { System.out.print(v.get(i) + ", "); } // 一个类集不能直接存储基本数据类型int，char，double等的值 // ArrayList <int> mylist1 = new ArrayList <int>(); ArrayList <int[]> mylist2 = new ArrayList <int[]>(); ArrayList <String> mylist3 = new ArrayList <String>(); ArrayList <Integer> mylist4 = new ArrayList <Integer>(); Map<String, String> map1 = new HashMap<String, String>(); Map<Integer, String> map2 = new HashMap<Integer, String>(); for (int j = 0; j < 10; j++) { map2.put(j, "Hello " + j); } System.out.println(); for(int j = 0; j < map2.size(); j++) { System.out.println(map2.get(j)); } } public String toString() { System.out.println("BBB" + this.m_iNum); return "Z"; } static void setInt(int i){ i++; System.out.println("setInt(): i = " + i); } // 奇数在前，偶数在后 public int[] fun(int[] arr) { int n = arr.length; int i = 0; int j = n - 1; while (i < j) { if (arr[i] % 2 != 0) { // odd number i++; } else { // even if (arr[j] % 2 != 0) { int temp = arr[i]; arr[i] = arr[j]; arr[j] = temp; } j--; } } return arr; } public static int maxInt(int[] arr, int n) { for(int i = 1; i < n; i++) { arr[0] = arr[i] > arr[0] ? arr[i]:arr[0]; } return arr[0]; } protected class Test1 extends Test{ public Test1(int count) { setInt(0); // 非静态内部类可以访问外部类的静态和非静态成员函数 toString(); System.out.println("mCount = " + mCount); // 非静态内部类只能访问外部类的非静态成员变量 } } static class Test2 extends Test{ public Test2(int count) { setInt(0); // 静态内部类可以访问外部类的静态和非静态成员函数 toString(); System.out.println("m_iNum = " + m_iNum); // 静态内部类只能访问外部类的静态成员变量 } } }