Java第六次作业

1使用for循环计算1-100的和，除了以3结尾的那些数

package com;

public class Test {

    /**
     * @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=sum+i;
            }
        }
        System.out.println(sum);

    }

}

package com;

public class Test {

    /**
     * @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=sum+i;
            }
        }
        System.out.println(sum);

    }

}

 

2.使用二重循环输出以下图形

package com;

public class Test2 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        for (int i = 1; i <=4; i++) {
            for (int j = 4-i; j >0; j--) {
                System.out.print(" ");
            }
            for (int m = 0; m < 2*i-1; m++) {
                System.out.print("*");
            }
            System.out.print("\n");
        }
        int z=5;
        for(int i=0;i<5;i++)
        {
           
          for(int j=0;j<i ;j++)
          {
            System.out.print(" ");
          }
          
          for(int k=0;k<z ;k++)
          {
            System.out.print("*");
          }
          z--;
          System.out.println();
        }
    }

}

 

 

 3.循环输入学生姓名，直到输入‘Q’程序结束

package com;

import java.util.Scanner;

public class Test1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input=new Scanner(System.in);
        System.out.println("请输入学生姓名");
        String name=input.next();
        if (name.equals("Q")) {
            System.out.println("结束");
        }else {
            System.out.println("请重新输入");
            name=input.next();
        }
    }
}

 

4.输入5个学生成绩，求和，当输入不合法的时候，提示输入错误重新输入。

package com;

import java.util.Scanner;

public class Test3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input=new Scanner(System.in);
        System.out.println("请输入5个学生成绩");
        int a=input.nextInt();
        int b=input.nextInt();
        int c=input.nextInt();
        int d=input.nextInt();
        int e=input.nextInt();
        int sum=0;
        if (a<0||a>100) {
            a=input.nextInt();
            System.out.println("请重新输入");
        }
        if (b<0||b>100) {
            b=input.nextInt();
            System.out.println("请重新输入");
        }
        if (c<0||c>100) {
            c=input.nextInt();
            System.out.println("请重新输入");
        }
        if (d<0||d>100) {
            d=input.nextInt();
            System.out.println("请重新输入");
        }
        if (e<0||e>100) {
            e=input.nextInt();
            System.out.println("请重新输入");
        }
        sum=sum+a+b+c+d+e;
        System.out.println("总成绩为"+sum);

    }

}

 

 5.计算 1+ 1/(1+2)+  1/(1+2+3)+  1/(1+2+3+4) +…………+1/(1+2+....+10)

 

package com;

 

public class Test4 {

 

    /**

     * @param args

     */

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        double sum=0,m=1;

        for (int i = 2; i <=10; i++) {

            m=m+i;

            sum=sum+(1/m);

        }

        System.out.println(sum+1);

 

    }

 

}

 

 

 1.产生一个1-99的随机数，猜数字，若大了就提示“大了点”，若小了就提示“小了点”直到猜对位置

package com;

import java.util.Random;
import java.util.Scanner;

public class Test5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Random r = new Random();
        int x = r.nextInt(100);
        System.out.println(x);
        Scanner input = new Scanner(System.in);
        System.out.println("输入1-99之间数");
        int a1 = 0;
        while (true) {
            int y = input.nextInt();
            a1++;
            if (y == x) {
                System.out.println("猜对了");
                break;
            } else if (y > x) {
                System.out.println("大了点");
                continue;
            } else if (y < x) {
                System.out.println("小了点");
                continue;
            }
        }

        if (a1 >= 1 && a1 <= 3) {
            System.out.println("太棒了");
        } else if (a1 >= 5 && a1 <= 8) {
            System.out.println("一般般");
        } else if (a1 >= 5 && a1 <= 8) {
            System.out.println("太笨了");
        }
    }
}

 

2.输入一个数，判断是不是质数（只能被1和自身整除的数是质数）

package com;

import java.util.Random;
import java.util.Scanner;

public class Test5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("请输入一个数");
        int a = input.nextInt();
        boolean b = true;
        for (int i = 2; i < a - 1; i++) {
            if (a % i == 0) {
                b = false;
                break;
            }
        }
        if (b) {
            System.out.println("该数是一个质数");
        } else {
            System.out.println("该数不是一个质数");
        }
    }
}

 

 3.求裴波那契数列的第20项是什么。裴波那契数列，1,1,2,3,5,8,13，21……

package com;

import java.util.Random;
import java.util.Scanner;

public class Test5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int x = 1;
        int y = 1;
        int z = 0;
        for (int i = 3; i < 21; i++) {
            z = x + y;
            x = y;
            y = z;
        }
        System.out.println("第20项为" + z);
    }
}