java第一次作业

1.定义圆形半径,求面积

package yyyy;

public class Wy {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int r=2;
        double area;
        area=3.14*r*r;
        System.out.println("圆的面积为:"+area);

    }

}

 

 

2.华氏温度和摄氏温度互相转换

package yyyy;

public class Wy {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        double hsd=100;
        double ssd;
        ssd=(hsd-32)*5/9;
        System.out.println("华氏度是:"+hsd+"摄氏度是:"+ssd);
        ssd=45;
        hsd=ssd*9/5+32;
        System.out.println("摄氏度是:"+ssd+"华氏度是:"+hsd);

    }

}

 

 

 

3.已知a,b均是整形变量,写出a,b两个变量中值互换的程序

package yyyy;

public class Wy {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a=2;
        int b=5;
        int c;
        c=a;
        a=b;
        b=c;
        System.out.println("a为"+a);
        System.out.println("b为"+b);
        }
    }

 

 

 4.定义一个任意的5位整数,将他保留到百位,无需四舍五入

 

package yyyy;

public class Wy {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        int a=12345;
        a=a%1000;
        System.out.println("a的值是:"+a);
        }
    }

 

5.输入0~1000的整数,求各位整数之和 

package yyyy;

import java.util.Scanner;

public class Wy {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input=new Scanner(System.in);
        System.out.println("输入一个0~1000的整数");
        int a=input.nextInt();
        System.out.println("该数各位数的和是:"+(a/100+a%100/10+a%10));
        }
}

 

6.定义一个任意的大写字母A~Z,转换为小写字母

package yyyy;

import java.util.Scanner;

public class Wy {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input=new Scanner(System.in);
        System.out.println("输入一个大写字母");
        char c=input.next().charAt(0);
        char xiaoxie=(char)(c+32);
        System.out.println("对应小写字母为:"+xiaoxie);
        }
    }

7.输入一个任意的小写字母a~z,转换为大写字母

package yyyy;

import java.util.Scanner;

public class Wy {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input=new Scanner(System.in);
        System.out.println("输入一个小写字母");
        char c=input.next().charAt(0);
        char daxie=(char)(c-32);
        System.out.println("对应大写字母为:"+daxie);
        }
    }