Java作业3

1. 定义圆形半径，求面积。int r =5;

package lll;

 

public class zhixiang {

 

         public static void main(String[] args) {

                  // TODO Auto-generated method stub

                  int a=3 ,r=5;

                  int s;

                  s=a*r*r;

                  System.out.println("圆的面积为"+s);

         }

 

}

2.华氏温度和摄氏温度互相转换，从华氏度变成摄氏度你只要减去32，乘以5再除以9就行了，将摄氏度转成华氏度，直接乘以9，除以5，再加上32即行。

package lll;

 

import java.util.Scanner;

 

public class zhixiang {

 

         public static void main(String[] args) {

                  // TODO Auto-generated method stub

                  Scanner input=new Scanner(System.in);

                  int h,s;

                  System.out.println("请输入华氏度：");

                  h=input.nextInt();

                  s=(h-32)*5/9;

                  System.out.println("相应的摄氏度为"+s);

                  System.out.println("请输入摄氏度：");

                  s=input.nextInt();

                  h=s*9/5+32;

                  System.out.println("相应的华氏度为"+h);

         }

 

}

3.已知a,b均是整型变量，写出将a,b两个变量中的值互换的程序。

package lll;

 

import java.util.Scanner;

 

public class zhixiang {

 

         public static void main(String[] args) {

                  // TODO Auto-generated method stub

                  int a,b,c;

                  Scanner input=new Scanner(System.in);

                  System.out.println("请输入两个数：");

                  a=input.nextInt();

                  b=input.nextInt();

                  c=a;

                  a=b;

                  b=c;

                  System.out.println("交换后的数是\n"+a +b);

         }

 

}

4.定义一个任意的5位整数，将它保留到百位，无需四舍五入（知识点：变量和运算符综合应用）

package lll;

 

import java.util.Scanner;

 

public class zhixiang {

 

         public static void main(String[] args) {

                  // TODO Auto-generated method stub

                  int a=12345,b;

                  b=a/100*100;

                  System.out.println("保留到百位是："+b);

         }

 

}

5.输入一个0～1000的整数，求各位数的和，例如345的结果是3+4+5＝12注：分解数字既可以先除后模也可以先模后除（知识点：变量和运算符综合应用）

package lll;

 

import java.util.Scanner;

 

public class zhixiang {

 

         public static void main(String[] args) {

                  // TODO Auto-generated method stub

                  Scanner input=new Scanner(System.in);

                  int a,g,s,b,h;

                  System.out.println("请输入一个0到1000的数：");

                  a=input.nextInt();

                  g=a%10;

                  s=a/10%10;

                  b=a/100;

                  h=g+s+b;

                  System.out.println("各位数的和是："+h);

         }

 

}

6定义一个任意的大写字母A~Z，转换为小写字母（知识点：变量和运算符综合应用） 

   package nb;

import java.util.Scanner;

public class gra {

 

    public static void main(String[] args) {

        // TODO Auto-generated method stub

        Scanner reader=new Scanner(System.in);

        char c='A',x;

        x=(char)(c+32);

        System.out.println("小写字母是："+x);

    }

 

}

 

7输入一个任意的小写字母a~z，转换为大写字母

  package nb;

import java.util.Scanner;

public class gra {

 

         public static void main(String[] args) {

                  // TODO Auto-generated method stub

                  Scanner reader=new Scanner(System.in);

                  char c,x;

                  System.out.println("请输入一个小写字母：");

                  c=reader.next().charAt(0);

                  x=(char)(c-32);

                  System.out.println("他的大写字母是："+x);

         }