Java第一次作业

1.定义圆形半径,求面积

public class text1 {

    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 text2 {

    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 text3 {

    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 text4 {

    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 text5 {

    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 text6 {

    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 text7 {

 

   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);

   }