Java中数组的定义和使用教程(三)

public class ArrayDemo {
	public static void main(String args[]) {
		int data[] = new int[] {9, 3, 1, 5, 4, 2, 7, 8, 6, 0};
		sort(data);
		printArray(data);
	}

	public static void sort(int arr[]) { //实现数组排序
		for(int x = 0; x < arr.length - 1; x++) {
			for(int y = 0; y < arr.length - x - 1; y++) {
				if(arr[y] > arr[y+1]) {
					int temp = arr[y];
					arr[y] = arr[y+1];
					arr[y+1] = temp;
				}
			}
		}
	}
	//定义一个专门进行数组输出的方法
	public static void printArray(int temp[]) {
		for (int i = 0; i < temp.length; i++) {
			System.out.print(temp[i] + "、");
		}
		System.out.println();
	}
}

public class ArrayDemo {
	public static void main(String args[]) {
		int data[] = new int[] {9, 3, 1, 5, 4, 2, 7, 8, 6, 0};
		data = reverse(data); //反转
		printArray(data);
	}
	public static int [] reverse(int arr[]) { 
		int temp[] = new int[arr.length];
		int foot = 0;
		for(int x = arr.length - 1; x >= 0; x--) {
			temp[foot++] = arr[x];
		}
		return temp;
	}
	//定义一个专门进行数组输出的方法
	public static void printArray(int temp[]) {
		for (int i = 0; i < temp.length; i++) {
			System.out.print(temp[i] + "、");
		}
		System.out.println();
	}
}

public class ArrayDemo {
	public static void main(String args[]) {
		int data[] = new int[] {9, 3, 1, 5, 4, 2, 7, 8, 6, 0};
		reverse(data); //反转
		printArray(data);
	}

	public static void reverse(int arr[]) {
		int center = arr.length / 2; //转换次数
		int head = 0; //头部开始索引
		int tail = arr.length - 1; //尾部开始索引
		for(int x = 0; x < center; x++) {
			int temp = arr[head];
			arr[head] = arr[tail];
			arr[tail] = temp;
			head++;
			tail--;
		}
	}
	//定义一个专门进行数组输出的方法
	public static void printArray(int temp[]) {
		for (int i = 0; i < temp.length; i++) {
			System.out.print(temp[i] + "、");
		}
		System.out.println();
	}
}

public class ArrayDemo {
	public static void main(String args[]) {
		int data[][] = new int[][] {{1, 2, 3}, {4, 5, 6},{7, 8, 9}};
		reverse(data); //反转
		printArray(data);
	}

	public static void reverse(int arr[][]) {
		for(int x = 0; x < arr.length; x++) {
			for(int y = x; y < arr[x].length; y++) {
				if(x != y) {
					int temp = arr[x][y];
					arr[x][y] = arr[y][x];
					arr[y][x] = temp;
				}
			}
		}
	}
	//定义一个专门进行数组输出的方法
	public static void printArray(int temp[][]) {
		for (int i = 0; i < temp.length; i++) {
			for(int j = 0; j < temp[i].length; j++) {
				System.out.print(temp[i][j] + "、");
			}
			System.out.println();
		}
		System.out.println();
	}
}

public class ArrayDemo {
	public static void main(String args[]) {
		int data[] = new int[] {1, 2, 3, 4, 5, 6, 7, 8};
		int search = 7;
		System.out.println(index(data, search));
	}
	public static int index(int arr[], int key) {
		for(int x = 0; x < arr.length; x++) {
			if(arr[x] == key)
				return x;
		}
		return -1;
	}
}

public class ArrayDemo {
	public static void main(String args[]) {
		int data[] = new int[] {1, 2, 3, 4, 5, 6, 7, 8};
		int search = 7;
		System.out.println(index(data, search));
	}
	public static int binarySearch(int arr[], int from, int to, int key) {
		if(from < to) {
			int mid = from / 2 + to / 2; //确定中间点
			if(arr[mid] = key) { //数据找到了
				return mid; // 取得当前索引
			}else if(key < arr[mid]) {
				return binarySearch(arr, from, mid - 1; key);
			}
			else(key > arr[mid]){
				return binarySearch(arr, mid + 1, to, key);
			}
		}
		return -1;
	}
}

class Person {
	private String name;
	private int age;

	public Person(String n, int a) {
		name = n;
		age = a;
	}
	public String getInfo() {
		return "姓名：" + name + "，年龄：" + age;
	}
}
public class ArrayDemo {
	// 动态初始化之后对象数组中的每一个元素都是其对象数据类型的默认值
	public static void main(String args[]) {
		Person per[] = new Person[3]; //动态初始化
		per[0] = new Person("张三", 1);
		per[1] = new Person("王五", 2);
		per[2] = new Person("李四", 4);
		for(int x = 0; x < per.length; x++) {
			System.out.println(per[x].getInfo());
		}
	}
}

class Person {
	private String name;
	private int age;

	public Person(String n, int a) {
		name = n;
		age = a;
	}
	public String getInfo() {
		return "姓名：" + name + "，年龄：" + age;
	}
}
public class ArrayDemo {
	// 动态初始化之后对象数组中的每一个元素都是其对象数据类型的默认值
	public static void main(String args[]) {
		Person per[] = new Person[] {
		new Person("张三", 1), 
		new Person("王五", 2),
		new Person("李四", 4)
		}; //动态初始化
		for(int x = 0; x < per.length; x++) {
			System.out.println(per[x].getInfo());
		}
	}
}