Java_数组/冒泡排序/查找

 

烦

public class HW09 {
	public static void main(String[] args) {
		double[] hens = {3, 5, 1, 3.4, 2, 50};
		double sum = 0.0;
		for (int i = 0; i < 6; ++i) {
			sum += hens[i];
		}
		System.out.println("sum = " + sum);
		System.out.println("avg = " + (sum / 6));
	}
}

double 表示是double类型的数组

hens是数组名

｛｝中的数字表示是数组的元素

我们可以通过hens[下标]来访问数组的元素，下标从0开始，这边是与地址相关的，可以方便计算地址。
数组名.length(leng长 + th表性质 = 长度)可以得到数组的长度。

 

 

 

 

 

import java.util.Scanner;

public class Array {
	public static void main(String[] args) {
		int[] arr = {1, 2, 3};
		char judge = 'y';
		Scanner myScanner = new Scanner(System.in);
		int i = 0;
		do {
			int[] arrNew = new int[arr.length + 1];
			for (i = 0; i < arr.length; ++i) {
				arrNew[i] = arr[i];
			}
			System.out.println("请输入你要插入的数字：");
			int num = myScanner.nextInt();
			arrNew[arr.length] = num;
			arr = arrNew;
			for (i = 0; i < arr.length; ++i) {
				System.out.print(arr[i] + " ");
			}
			System.out.println("\n还要继续插入数字吗？y/n:>");
			judge = myScanner.next().charAt(0);
		}while (judge != 'n');
	}
}

import java.util.Scanner;

public class ArrayReduce {
	public static void main(String[] args) {
		int[] arr = {1, 2, 3, 4, 5};
		char judge = 'y';
		Scanner myScanner = new Scanner(System.in);
		do {
			int[] arrNew = new int[arr.length - 1];
			for (int i = 0; i < arr.length - 1; ++i) {
				arrNew[i] = arr[i];
			}
			arr = arrNew;
			for (int i = 0; i < arr.length; ++i) {
				System.out.print(arr[i] + "\t");
			}
			if (arr.length == 0) {
				System.out.println("不能删了哦~");
				break;
			}
			System.out.println("还要继续删吗？");
			judge = myScanner.next().charAt(0);
		}while (judge != 'n');
	}
}

 

 

public class BubbleSort {
	public static void main(String[] args) {
		int[] arr = {28, 23, 99, 91, 8};
		for (int i = 0; i < arr.length - 1; ++i) {
			for (int j = 0; j < arr.length - 1 - i; ++j) {
				if (arr[j] > arr[j+1]) {
					int temp = arr[j];
					arr[j] = arr[j+1];
					arr[j+1] = temp;
				}
			}
		}
		for (int i = 0; i < arr.length; ++i) {
			System.out.print(arr[i] + "\t");
		}
	}
}

 

我的

import java.util.Scanner;

public class SeqSearch {
	public static void main(String[] args) {
		String[] str = {"白", "金", "紫", "青"};
		Scanner myScanner = new Scanner(System.in);
		System.out.println("请输入一个名称：");
		String name = myScanner.next();
		for (int i = 0; i < str.length; ++i) {
			if (str[i].equals(name)) {
				System.out.println("找到了！");
				System.out.println("下标是" + i);
				return;
			}
		}
		System.out.println("没有找到!");
	}
}

老师

import java.util.Scanner;

public class SeqSearch {
	public static void main(String[] args) {
		String[] str = {"白", "金", "紫", "青"};
		Scanner myScanner = new Scanner(System.in);
		System.out.println("请输入一个名称：");
		String name = myScanner.next();
		int index = -1;
		for (int i = 0; i < str.length; ++i) {
			if (str[i].equals(name)) {
				System.out.println("找到了！");
				System.out.println("下标是" + i);
				index = i;
				break;
			}
		}
		if (index == -1) {
			System.out.println("没有找到!" + name);
		}
	}
}