java第二次作业

1．编写一个程序，定义圆的半径,求圆的面积.

package home;
import java.util.Scanner;
public class zuoye {

/**
* @param args
*/
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.print("输入圆的半径: ");
double r = s.nextDouble();
double ss = 3.14 * r * r;
System.out.println("圆的面积是: " + ss);

}

}

2．华氏温度和摄氏温度互相转换

package home;
import java.util.Scanner;
public class zuoye {

/**
* @param args
*/
public static void main(String[] args) {
System.out.println("选择你要转换的温度:");
System.out.print("摄氏度" + "\t" + "华氏度");
Scanner s = new Scanner(System.in);
String x = s.next();
if ("摄氏度".equals(x)) {
System.out.println("输入华氏度: ");
Scanner a = new Scanner(System.in);
double h = a.nextDouble();
System.out.println("摄氏度: " + (h - 32.00) * 5.00 / 9.00);
}
if ("华氏度".equals(x)) {
System.out.println("输入摄氏度: ");
Scanner b = new Scanner(System.in);
double ss = b.nextDouble();
System.out.println("华氏度: " + (((ss * 9.00)/5.00  + 32.00)));
}
}

}

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 home;

public class zuoye {

/**
* @param args
*/
public static void main(String[] args) {
int a = 5;
int b = 8;
System.out.println(a + "\t" + b);
int s= a;
a = b;
b = s;
System.out.println(a + "\t" + 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

package home;
import java.util.Scanner;
public class zuoye {

/**
* @param args
*/
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.print("输入五位整数: ");
int x = s.nextInt();
int w = x / 100 * 100;
System.out.println("精确到百位: " + w);
}

}

5．输入一个0～1000的整数，求各位数的和

package home;
import java.util.Scanner;
//输入数字求各位数的和
public class zuoye {

/**
* @param args
*/
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.println("请输入数字: ");
int x = s.nextInt();
if (x>1000 || x<0) {
System.out.println("输入数字不合法");
return;
}else if (x/1000 == 1) {
System.out.println("数字和是：1");
return;
}else if (x/100 != 0) {
System.out.println("数字的和是: " + (x/100+x%100/10+x%10));
return;
}else if (x/10 != 0) {
System.out.println("数字的和是: " + (x/10 + x%10));
return;
}else {
System.out.println("数字的和是: " + x);
}
}

}

6．定义一个任意的大写字母A~Z，转换为小写字母

package home;

public class zuoye {

/**
* @param args
*/
public static void main(String[] args) {
String str1 = "A";
String str2 = "a";

String str11 = str1.toLowerCase();
String str22 = str2.toUpperCase();

System.out.println(str1 + ": " + str11);
System.out.println(str2 + ": " + str22);
}

}

posted @ 2021-03-12 09:42  于国庆  阅读(55)  评论(0编辑  收藏  举报