第四次作业

package aaa;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        

            int sum=0;

            for(int i=1;i<=100;i++) {

                if(i%10!=3)

                    sum+=i;

            }

            System.out.println(sum);

        }
}

 

 

package aaa;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {


        for(int i=1;i<=4;i++) {

            for(int j=1;j<=4-i;j++) {

                System.out.print(" ");

            }

            for(int a=1;a<=2*i-1;a++) {

                System.out.print("*");

            }

            System.out.println();

        }

        System.out.println(" ");

        for(int i=1;i<=5;i++) {

            for(int j=1;j<=6-i;j++) {

                System.out.print("*");

            }

            System.out.println();

        }

    }
}

 

 

package aaa;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {


        Scanner input=new Scanner(System.in);

        while(true) {

            System.out.println("请输入学生姓名");

            String a=input.next();

            if(a.equals("Q")) {

                System.out.println("输入的名字有效");

                break;

            }else

                System.out.println("输入的名字无效,请重新输入");

        }

    }
}

 

package aaa;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {


        Scanner input=new Scanner(System.in);

        int sum=0;

        int i=0;

        while(i<=4) {

            System.out.println("请输入第"+(i+1)+"个学生的成绩");

            int grade=input.nextInt();



            if(grade<0||grade>100)

            {

                System.out.println("输入错误，请重新输入");

            }

            else {

                i++;

                sum+=grade;

            }

        }

        System.out.println("学生总成绩为"+sum);

    }

 

 

package aaa;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {


        double sum=0;

        double j=0;

        for(int i=1;i<=10;i++) {

            sum+=i;

            j=1/sum+j;

        }

        System.out.println(j);

    }
}

}

package aaa;
import java.util.Random;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {


        Random b = new Random();
        int x = b.nextInt(101);
        Scanner input = new Scanner(System.in);
        int num = 0;
        while (true) {
            num++;
            System.out.println("请输入");
            int i = input.nextInt();
            if (i > x) {
                System.out.println("大了点");
            } else if (i < x) {
                System.out.println("小了点");
            } else {
                System.out.println("答对了");
                break;
            }
        }
        System.out.println("一共猜了" + num + "次");
        if (num <= 3) {
            System.out.println("太棒了");
        } else if (num > 5 && num < 6) {
            System.out.println("一般般");
        } else {
            System.out.println("太笨了");

        }
    }
}

 

 

package aaa;
import java.util.Random;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner input=new Scanner(System.in);
        System.out.println("输入一个数");
        int num = input.nextInt();
        boolean isPrime = true;
        if (num == 1) {
            isPrime = false;
        }
        for (int i = 2; i <= num - 1; i++) {
            if (num % i == 0) {
                isPrime = false;
                break;
            }
        }

        if (isPrime) {
            System.out.println(num + "是质数");
        } else {
            System.out.println(num + "不是质数");
        }
    }
}

 

package aaa;
import java.util.Random;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        int a=1;
        int b=1;
        int c=0;
        for(int i=1;i<=18;i++){
            c=a+b;
            a=b;
            b=c;
        }
        System.out.println(c);
    }
}