第一次作业

1.定义圆形半径,求面积

public class aaa {

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        int r=4;

        double pai=3.14;

        double area;

        area=pai*r*r;

        System.out.println("圆的半径是:"+r+"\n圆的面积是:"+area);

    }

 

 

 

 

2.华氏温度和摄氏温度互相转换

public class aaa {

 

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        double h=50;

        double s;

        s=(h-32)*5/9;

        System.out.println("华氏度是:"+h+"摄氏度是:"+s);

        s=45;

        h=s*9/5+32;

        System.out.println("摄氏度是:"+s+"华氏度是:"+h);

    }

 

 

 

 

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

public class aaa {

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        int a=4;

        int b=3;

        int c=a;

        a=b;

        b=c;

        System.out.println("a的值是:"+a+"\nb的值是:"+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

public class aaa {

 

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        int a=42315;

        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

import java.util.Scanner;

 

public class aaa {

 

    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();

        int b,c,d,sum;

        b=a/100;

        c=a%100/10;

        d=a%10;

        sum=b+c+d;

        System.out.println("该数各位数的和是:"+sum);

    }

 

 

6.定义一个任意的大写字母A~Z,转换为小写字母

public class aaa {

 

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        int x='A';

        char b=(char) (x+32);

        System.out.println(b);

    }

 

 

 

7.输入一个任意的小写字母a~z,转换为大写字母

import java.util.Scanner;

public class aaa {

   public static void main(String[] args) {

 

      // TODO Auto-generated method stub

 

      Scanner input=new Scanner(System.in);

 

      System.out.println("请输入a~z任意一个字母");

 

      char word= input.next().charAt(0);

 

      char a=(char)(word-32);

 

      System.out.println("大写字母是:"+a);

 

   }