8.3 [JavaSE] 嵌套循环.数组.冒泡排序.插入排序

嵌套循环

嵌套循环练习：

for (int i = 1; i <=4; i++) {
            System.out.println("");
            for (int j = 1; j <= 5; j++) {
                System.out.print("*");
            }
        }

for (int i = 0; i <=5; i++) {
            System.out.println("");
            for (int j = 0; j 

for (int i = 1; i <=9 ; i++) {
            for (int j=1;j<=i;j++){
                System.out.print(j+"*"+i+"="+(j*i)+"\t");
            }
            System.out.println("");
        }

数组

数组的定义

数组的初始化

数组在内存中的理解

两个数组的内存图

数组的两大异常：

数组索引越界异常

空指针异常

数组练习

冒泡排序

冒泡排序代码示范：

int [] arr = {34,253,1,658,45,111};
		int temp;
		for(int i = 0; i < arr.length-1; i++) {//轮数
			for(int j = 0; j < arr.length-1 - i; j++) {//次数
				//比较 和 互换
				if(arr[j] > arr[j+1]) {
					temp = arr[j];
					arr[j] = arr[j+1];
					arr[j+1] = temp;
				}
			}
		}
		for(int a : arr) {
			System.out.println(a);

冒泡排序练习：

 public static void main(String[] args) {
        char[] a=new char[]{'a','c','u','b','e','p','f','z'};
        System.out.println("原字符序列："+Arrays.toString(a));
        char temp=a[0];
        for (int i = 0; i a[j+1]){
                    temp=a[j];
                    a[j]=a[j+1];
                    a[j+1]=temp;
                }
            }
        }
        System.out.println("升序排序后："+Arrays.toString(a));
        for (int i = 0; i 

插入排序

插入排序代码示范：

public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入你想插入的值：");
        int num = input.nextInt();
        int[] a = new int[11];//动态定义数组
        a[0] = 10;
        a[1] = 20;
        a[2] = 30;
        a[3] = 40;
        a[4] = 50;
        a[5] = 60;
        a[6] = 70;
        a[7] = 80;
        a[8] = 90;
        a[9] = 100;
        int maxNum = a[0];
        for (int i = 0; i < a.length; i++) {
            if (a[i] > maxNum) {
                maxNum = a[i];
            }
        }
        if (num > maxNum) {
            a[a.length - 1] = num;
        } else {
            int index = -1;
            for (int i = 0; i < a.length; i++) {
                if (a[i] > num) {
                    index = i;
                    break;
                }
            }
            for (int i = a.length - 1; i > index; i--) {
                a[i] = a[i - 1];
            }
            a[index] = num;
        }

        System.out.println(Arrays.toString(a));
    }

插入排序练习:

public static void main(String[] args) {
        char[] a=new char[9];
        a[0]='a';
        a[1]='b';
        a[2]='c';
        a[3]='e';
        a[4]='f';
        a[5]='p';
        a[6]='u';
        a[7]='z';
        char temp='m';
        System.out.print("原字符序列：");
        for (int i = 0; i index;i--){
            a[i]=a[i-1];
        }
        a[index]=temp;
        System.out.print("插入后的字符序列是：");
        for (int i = 0; i < a.length ; i++) {
            System.out.print(a[i]+"\t");
        }
    }