java第一次作业

package aaa;
import java.util.Random;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        double r = 5;
        double mian = 0;
        mian = r * r * 3.14;
        System.out.println("园的面积为" + mian);
    }
}

 

 

package aaa;
import java.util.Random;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.println("请输入（1/0）");

        System.out.println("1.输入摄氏度  2.输入华氏度"  );

        int i = sc.nextInt();

        if(i == 1) {

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

            double s = sc.nextDouble();

            double h = s * 9 / 5 + 32;

            System.out.println( "摄氏度"+ s + "温度转换为摄氏温度为" + h + "度");

        }

        if(i == 0) {

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

            double h = sc.nextDouble();

            double s = (h - 32) * 5 / 9;

            System.out.println( "华氏摄氏度"+ h + "温度转换为摄氏温度为" + s + "度");

        }

    
    }
}

 

package aaa;
import java.util.Random;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        int a = 5;

        int b = 6;

        int temp = 0;

        temp = a;

        a = b;

        b = temp;

        System.out.println("交换过后" + ",a =" + a + ",b =" + b);

    }
}

 

package aaa;
import java.util.Random;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        int a = 12345;

        a = a /10 /10;

        System.out.println(a);

    }
}

 

 

package aaa;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.println("请输入一个0 ~ 1000的整数");

        int shu = sc.nextInt();

        int ge = shu % 10;

        int shi = shu % 100 / 10;

        int bai = shu / 100  % 10;

        int qian = shu / 1000;

        System.out.println("个位是" + ge);

        System.out.println("十位是" + shi);

        System.out.println("百位是" + bai);

        System.out.println("千位是" + qian);

    }
}

 

 

package aaa;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        char zi = 'A';
        char xzi = (char)(zi + 32);
        System.out.println(xzi);
    }
}

 

 

 

 

 

 

package aaa;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        String s = sc.next();

        char zi = s.charAt(0);

        char xzi = (char)(zi - 32);

        System.out.println(xzi);
    }
}