3.12第二次作业
1．编写一个程序，定义圆的半径,求圆的面积.
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package Homework;import java.util.Scanner;public class A3 { 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
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package Homework;import java.util.Scanner;//摄氏度华氏度转换public class A2 { 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。
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package Homework;public class A4 { public static void main(String[] args) { int a = 5; int b = 8; System.out.println(a + "\t" + b); int x= a; a = b; b = x; 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
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package Homework;import java.util.Scanner;public class A5 { 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
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package Homework;import java.util.Scanner;//输入数字求各位数的和public class A1 { 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
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package Homework;public class A6 { 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); }} |
