4.1第五周java课上练习

1.编写程序,判断一个变量x的值,如果是1,输出x=1,如果是5,输出x=5,如果是10,输出x=10,除了以上几个值,都输出x=none.

package com.ym.home;

import java.util.Scanner;

public class HM1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("请输入一个数");
        int x = input.nextInt();
        if (x == 1 || x == 5 || x == 10) {
            System.out.println("x=" + x);
        } else {
            System.out.println("none");
        }
    }

}

 

2.输入年份月份,输出该月的天数(闰年2月29天)

package com.ym.home;

import java.util.Scanner;

public class HM2 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("输入年份");
        int year = input.nextInt();
        System.out.println("输入月份");
        int m = input.nextInt();
        boolean isrun = year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
        // if (m == 4 || m == 6 || m == 9 || m == 11) {
        // System.out.println("30天");
        // } else if (m == 2 && isrun) {
        // System.out.println("29天");
        // } else if (m == 2 && !isrun) {
        // System.out.println("28天");
        // } else {
        // System.out.println("31天");
        // }
        switch (m) {
        case 4:
        case 6:
        case 9:
        case 11:
            System.out.println("30天");
            break;
        case 2:
            if (isrun)
                System.out.println("29天");
             else 
                System.out.println("28天");
                break;
            default:
                System.out.println("31天");
            }
        }
    }

 

3.输出1-100所有数

package com.ym.loop;

public class PT1 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int i = 1;
        while (i <= 100) {
            System.out.println(i);
            i++;
        }
    }

}

4.输出1-100所有奇数

package com.ym.loop;

public class PT2 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int i = 1;
        while (i <= 100) {
            if (i % 2 != 0)
                System.out.println(i);
            i++;
        }
    }

}

5.输出1-100所有偶数

package com.ym.loop;

public class PT3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int i = 1;
        while (i <= 100) {
            if (i % 2 == 0)
                System.out.println(i);
            i++;
        }
    }

}

6.输出1-100能被7整除的所有数

package com.ym.loop;

public class PT4 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int i = 1;
        while (i <= 100) {
            if (i % 7 == 0)
                System.out.println(i);
            i++;
        }
    }

}

7.输出1-100既能被3又能被5整除的数

package com.ym.loop;

public class PT5 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int i = 1;
        while (i <= 100) {
            if (i % 3 == 0 && i % 5 == 0)
                System.out.println(i);
            i++;
        }
    }

}

 

 8.输出100-999所有水仙花数

package com.ym.loop;

public class PT6 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int i = 100;
        while (i <= 999) {
            int ge = i % 10;
            int shi = i / 10 % 10;
            int bai = i / 100;
            if (ge * ge * ge + shi * shi * shi + bai * bai * bai == i)
                System.out.println(i);
            i++;
        }

    }

}

 

 9.输入2个数,输出他们中间的所有数.

package com.ym.loop;

import java.util.Scanner;

public class PT7 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("输入第一个数");
        int a = input.nextInt();
        System.out.println("输入第二个数");
        int b = input.nextInt();
        int i = a + 1;
        while (i <= b - 1) {
            System.out.println(i);
            i++;
        }
    }

}

 

 10.1-100求和.

package com.ym.loop;

public class PT8 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int sum = 0;
        int i = 1;
        while (i <= 100) {
            sum += i;
            i++;
        }
        System.out.println(sum);
    }

}

 

 11.1-100能被3整除的求和.

package com.ym.loop;

public class PT8 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int sum = 0;
        int i = 1;
        while (i <= 100) {
            if(i%3==0)
            sum += i;
            i++;
        }
        System.out.println(sum);
    }

}

 

 12.1-100既能被3又能被5整除的数求和.

package com.ym.loop;

public class PT8 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int sum = 0;
        int i = 1;
        while (i <= 100) {
            if (i % 3 == 0 && i % 5 == 0)
                sum += i;
            i++;
        }
        System.out.println(sum);
    }

}

 

 13.输入2个数,输出他们中间数的和.

package com.ym.loop;

import java.util.Scanner;

public class PT9 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("输入第一个数");
        int a = input.nextInt();
        System.out.println("输入第二个数");
        int b = input.nextInt();
        int sum = 0;
        int i = a + 1;
        while (i <= b - 1) {
            sum += i;
            i++;
        }
        System.out.println(sum);
    }

}

 

14.输入一个数,求阶乘.

package com.ym.loop;

import java.util.Scanner;

public class PT8 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        System.out.println("输入一个数");
        int x = input.nextInt();
        int sum = 1;
        int i = 1;
        while (i <= x) {
            sum *= i;
            i++;
        }
        System.out.println(sum);
    }

}

15.1-100偶数和.

package com.ym.loop;

public class PT3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int sum = 0;
        int i = 1;
        while (i <= 100) {
            if (i % 2 == 0)
                sum += i;
            i++;
        }
        System.out.println(sum);
    }

}

 

16.1-100奇数和

 

package com.ym.loop;

public class PT3 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int sum = 0;
        int i = 1;
        while (i <= 100) {
            if (i % 2 != 0)
                sum += i;
            i++;
        }
        System.out.println(sum);
    }

}