刷题的狂欢-----JAVA每日三练-----第十八天

Posted 2021-11-02 敲代码的xiaolang

努力刷题，每日三题。-------题目来源 “牛客网”

第一题

import java.util.Arrays;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
         int[] arr = new int[7];
        for (int i = 0; i < arr.length; i++) {
                    arr[i] = scanner.nextInt();
                }
        scanner.close();

        for(int j = 0; j < 7; j++){
            for(int l = 0; l < 6-j; l++){
                if(arr[l] > arr[l+1]){
                    int temp;
                    temp = arr[l];
                    arr[l] = arr[l+1];
                    arr[l+1] = temp;
                }
            }
        }
        

        for (int k = 0;k < arr.length; k++) {
                    System.out.print(arr[k]+" ");
                 }
        }
}

第二题

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextDouble()) {
            double s = scanner.nextDouble();
            System.out.println(String.format("%.3f",new Circle(s).getArea()));
            System.out.println(String.format("%.3f", new Square(s).getArea()));
        }
    }

}

class Shape {

    private double s; // 周长

    public Shape(double s) {
        this.s = s;
    }

    public double getS() {
        return s;
    }

}

interface Area {
    double getArea(); // 面积
}

// 圆形
class Circle extends Shape implements Area {

    public Circle(double s) {
        super(s);
    }
    public double getArea() {
        double r = getS()/(Math.PI*2);
        double area = Math.PI*r*r;
        return area;
    }
}

// 方形
class Square extends Shape implements Area {


    public Square(double s) {
        super(s);
    }
    public double getArea() {
        double r = getS()/4;
        double area = r*r;
        return area;
    }
}

第三题

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int start = scanner.nextInt();
        int end = scanner.nextInt();
        method(start,end);

    }
    public static void method(int start,int end){
        int count=0;
        if(end < start){
            int temp = start;
            start = end;
            end = temp;
        }

        if(end == start){ //此处使用if，而不是else if
            count = 0;
        }

        else{
            int i,start1;
            int number=0;
            if(start <3){
                start1 = 3;
            }
            else{
                start1 = start;
            }
            for(i = start1; i <= end; i++){
                int j;
                for(j = 1; j <= i; j++){
                    if(i%j==0){
                        number = number + 1;
                    }
                  }
                 if(number <= 2){
                        count++;
                }
                number = 0;
            }
        }
        System.out.println(start+"到"+end+"之间有"+count+"个素数");

    }
}

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https://blog.csdn.net/weixin_52605156/article/details/120689189?spm=1001.2014.3001.5501