Java基础面试1(基础)

喜欢ヅ旅行 2022-12-01 05:28 186阅读 0赞

### Java基础面试1.面试算法练习.后端开发 ###

*  0. 目录
 *  1. Java基础面试1
 *   *  1.1 基础1
     *   *  1.1.1 冒泡排序
         *  1.1.2 二分查找
         *  1.1.3 时间类型转换
         *  1.1.4 阶乘

# 0. 目录 #

# 1. Java基础面试1 #

## 1.1 基础1 ##

### 1.1.1 冒泡排序 ###

import java.util.Scanner;
    
    //冒泡排序-Java
    public class Sort{
        private static int data[]={12,10,6,7,3,16,9};
    
        public static void input() {
            Scanner scanner=new Scanner(System.in);
            System.out.println("请输入10个排序的数据: ");
    
            for(int i=1;i<data.length;i++){
                data[i]=scanner.nextInt();
            }   
        }
    
        public static void bubbleSort(int array[]) {
            boolean flag=false;
    
            for(int i=0;i<array.length-1;i++){
                flag=false;
    
                for(int j=array.length-1;j>i;j--){
                    if(array[j-1]>array[j]){
                        int temp=array[j-1];
                        array[j-1]=array[j];
                        array[j]=temp;
                        flag=true;
                    }
                }
    
                if(flag==false){
                    return;
                }
                output();
            }
        }
    
        protected static void output(){
            System.out.println("顺序为:");
            for(int i=0;i<data.length;i++){
                System.out.print(data[i]+" ");
            }
            System.out.println();
        }
    
        public static void main(String[] args) {
            //input();
            output();
            bubbleSort(data);
            output();
        }
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjQ3MzIyOA_size_16_color_FFFFFF_t_70_pic_center]

### 1.1.2 二分查找 ###

public class Search {
        private static int data[]={1,2,3,4,5,6,7,8,9,10};
    
        //适用于有序
        public static int binarySearch(int array[],int key){
            int low=0,high=array.length-1,mid;
            while(low<=high){
                mid=(low+high)/2;
                if(array[mid]==key){
                    return mid;
                }
                else if(array[mid]>key){
                    high=mid-1;
                }
                else{
                    low=mid+1;
                }
                System.out.println("这是一趟");
            }
            return -1;
        }
    
        public static void main(String[] args) {
            System.out.println(binarySearch(data, 7));
        }
    }

![在这里插入图片描述][20200826143431303.png_pic_center]

### 1.1.3 时间类型转换 ###

import java.text.ParseException;
    import java.text.SimpleDateFormat;
    
    public class DateFormat {
        private static String myDate = "20200825";
    
        public static void fun() {
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy 年 MM 月 dd 日");
            String newDate;
            try {
                newDate = sdf.format(new SimpleDateFormat("yyyyMMdd").parse(myDate));
                System.out.println(newDate);
            } catch (ParseException e) {
                e.printStackTrace();
            }
        }
    
        public static void main(String[] args) {
            fun();
        }
    }

![在这里插入图片描述][20200826141543358.png_pic_center]

### 1.1.4 阶乘 ###

public class Factorial {
        
        protected static int multiply(int num){
            if(num<0){
                System.out.println("请输入大于0的数!");
                return -1;
            }else if(num==0||num==1){
                return 1;
            }else{
                return multiply(num-1)*num;
            }
        }
    
        public static void main(String[] args) {
            System.out.println(multiply(10));
        }
    }

![在这里插入图片描述][20200826141613673.png_pic_center]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjQ3MzIyOA_size_16_color_FFFFFF_t_70_pic_center]: /images/20221123/72f08c7b428a4e78b17814fda619545b.png
[20200826143431303.png_pic_center]: /images/20221123/48e056c609ee4987a23f3ac22d641adc.png
[20200826141543358.png_pic_center]: /images/20221123/ba6ebe4af3af4552b87e6c94104d0446.png
[20200826141613673.png_pic_center]: /images/20221123/262fa2cc0048494e8b0f446d51722df0.png