Java第6次作业

1.

package bbc;

public class j1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int sum=0;
        for (int i = 1; i <=100; i++) {
            if(i%10!=3){
                sum+=i;
            }
        }
        System.out.println("和是"+sum);
    }

}

2.

package bbc;

public class h3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        for (int i = 1; i <=5; i++) {
            for (int j = 1; j <=5-i; j++) {
                System.out.print(" ");
            }
            for (int k = 1; k <=(2*i-1); k++) {
                System.out.print("*");
            }
            System.out.println();
        }
        
            System.out.println();
    }

}

3.

package bbc;

import java.util.Scanner;

public class j4 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        System.out.println("请输入");
        Scanner sc=new Scanner(System.in);
        while(true){
        String name=sc.next();
        if(name.equals("Q")){
            System.out.println("退出程序");
            break;
           }
        System.out.println("请输入");
        }
    }

}

4.

package bbc;

import java.util.Scanner;

public class j5 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        Scanner sc=new Scanner(System.in);
        int sum=0;
        for (int i = 1; i <=5; i++) {
            System.out.println("请输入第"+i+"个学生成绩");
            int a=sc.nextInt();
            if(a<0||a>100){
             System.out.println("输入错误重新输入");
            }
            sum+=a;
        }
        System.out.println(""+sum);
    }

}

5.

package bbc;

public class j6 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        double sum=0;
        double b=0;
        for (int i = 1; i <= 10; i++) {
            b+=i;
            sum+=1/b;
        }
        System.out.println("和是"+sum);
    }

}

6.

package bf;

import java.util.Scanner;

public class j1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a=(int)(Math.random()*100);
        Scanner sc=new Scanner(System.in);
        int count=0;
        while(true){
            count++;
            System.out.println("请输入数字");
            int i=sc.nextInt();
            if(i>a){
                System.out.println("猜大了");
            }
            if(i<a){
                System.out.println("猜小了");
            }
            if(i==a){
                System.out.println("猜对了,共猜了:"+count+"次");
            }
            
        }

    }

}

7.

public static void main(String[] args) {
        // TODO Auto-generated method stub

        boolean isPrime=true;
        System.out.println("请输入数");
        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt();
        if(a>0){
        for(int i=2;i<a;i++){
            if(a%i!=0){
                isPrime=false;
                break;
              }
           }
        }
        if(isPrime){
            System.out.println("不是质数");
        }
        else{
            System.out.println("是质数");
        }
    }

}

8.

package bf;


public class j3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a=1;
        int b=1;
        int sum=0;
        for(int i=3;i<=20;i++){
            sum=a+b;
            b=a;
            a=sum;
        }
        System.out.println("sum="+sum);
    }

}