【刷题学习Java】——循环语句

文章目录

• • 数列求和
  • 统计输入正数个数
  • 求最小公倍数
  • 小球走过路程计算
  • 求平均数
  • 判断质数
  • 计算整数位数
  • • 结尾

数列求和

public class Main {
    public static void main(String[] args) {

        //write your code here........
        long sum = 0;
        for(int i = 1;i <= 10; i++){
            sum+=(Math.pow(10,i))-1;
        }
        System.out.println(sum);
    }
}

统计输入正数个数

import java.util.*;

public class Main {
    public static void main(String[] args) {
        int count = 0;
        Scanner scanner = new Scanner(System.in);

        //write your code here......
        while(true){
            if((scanner.nextInt())<=0){
                break;
            }
          count++;
        }
        System.out.println(count);
    }
}

求最小公倍数

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner console = new Scanner(System.in);
        int m = console.nextInt();
        int n = console.nextInt();
        int result = getCM(m, n);
        System.out.println(result);
    }

    public static int getCM(int m, int n){
        
        //write your code here......
         
         //计算m、n中较大者
        int max=Math.max(m,n);
        //从max到m*n之间找最小公倍数
        for(int i=max;i<=m*n;i++){
            //如果既能被m整除又能被n整除，说明是最小公倍数，直接返回
            if(i%m==0&&i%n==0){
                return i;
            }
        }
        return 0;
    }
}

小球走过路程计算

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        float h=scanner.nextFloat();
        int n =scanner.nextInt();

        //write your code here......
        float dis = 0;
        for(int i = 0;i < n;i ++){
            dis += h;
            h /= 2;
            if(i == n-1){
              System.out.println(String.format("%.3f", h)+" "+String.format("%.3f", dis));  
            }
            dis += h;
        }
    }
}

求平均数

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        //write your code here......
        int cnt = 0;
        double avg = 0;
        int sum = 0;
        while(true){
            int num =  scan.nextInt();
            if(num < 0){
                break;
            }
            sum += num;
            cnt++;
        }
        avg = (double)sum / cnt;
        System.out.println(String.format("%.2f",avg));
        //输出格式为：System.out.println(String.format("%.2f",avg));
    }
}

判断质数

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        Scanner scan = new Scanner(System.in);
        int number = scan.nextInt();
        System.out.println(main.isPrimeNumber(number));
    }

    public Boolean isPrimeNumber(int number) {

        //write your code here......
        for(int i = 2;i < number;i ++){
            if(number % i == 0){
                return false;
            }
        }
        return true;
    }
}

计算整数位数

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int num = scan.nextInt();
        scan.close();

        //write code here......
        int cnt = 0;
        while(num > 0){
            cnt++;
            num /= 10;
        }
        System.out.println(cnt);
        if(num < 0){
            System.out.println(num);
        }
    }
}

结尾