基礎作業(yè)附答案

1、1. X (x<1) Y= 2x-1 (1<x<10) 3x-11 (x>10) 要求輸入x值后，輸出y值。package student.xiaoqiao.day01;；public class Yi public static void main(String args) System.out.println("請輸入一個數(shù)");Scanner sc = new Scanner(System.in);int x = sc.nextInt();if (x < 1) System.out.println("y=" + x);

2、if (x > 1 & x < 10) System.out.println("y=" + (2 * x - 1);if (x > 10) System.out.println("y=" + (3 * x - 11);2. 輸入一個年份判斷year是否是閏年package student.xiaoqiao.day01;import java.util.Scanner;public class Er public static void main(String args) System.out.println("請輸入年

3、份");Scanner sc=new Scanner(System.in);int year=sc.nextInt();if(year%4=0&year%100!=0)|(year%400=0)System.out.println("是閏年");else System.out.println("不是閏年");3. 任意輸入a,b,c 3個數(shù)判斷a，b，c大小package student.xiaoqiao.day01;import java.util.Scanner;public class San public static void

4、 main(String args) System.out.println("請輸入三個數(shù)（加空格或回車）:");Scanner sc = new Scanner(System.in);int x = sc.nextInt();int y = sc.nextInt();int z = sc.nextInt();if (x > y & x > z) System.out.println(x); else if (x < y & z < y) System.out.println(y); else if (x < z & y

5、 < z) System.out.println(z);4_1輸出圖形 * *package student.xiaoqiao.day01;public class Si_1 public static void main(String args) int temp = 3;for (int i = 1; i <= temp; i+) for (int j = 1; j <= temp - i; j+) System.out.print(" ");for (int k = 1; k <= 2 * i - 1; k+) System.out.print

6、("*");System.out.print('n');4_2輸出圖形* * *package student.xiaoqiao.day01;public class Si_1 public static void main(String args) int temp = 3;for (int i = 1; i <= temp; i+) for (int j = 1; j <= temp - i; j+) System.out.print(" ");for (int k = 1; k <= 2 * i - 1; k+)

7、System.out.print("*");System.out.print('n');4_3輸出圖形任意輸入n當輸入n值為1時，輸出 *當輸入n值為2時，輸出 當輸入n值為3時，輸出 .。當輸入n值為5時，輸出 * * * * * * *package student.xiaoqiao.day01;import java.util.Scanner;public class Si_3 public static void main(String args) System.out.println("請輸入一個數(shù)：");Scanner sc=

8、new Scanner(System.in);int temp = sc.nextInt();for (int i = 1; i <= temp; i+) for (int j = 1; j <= temp - i; j+) System.out.print(" ");for (int k = 1; k <= 2 * i - 1; k+) System.out.print("*");System.out.print('n');for (int i = temp; i >= 1; i-) for (int j = i

9、-1; j < temp; j+) System.out.print(" ");for (int k = 1; k <= 2 * i - 3; k+) System.out.print("*");System.out.print('n');4_4 輸出圖形 * *package student.xiaoqiao.day01;public class Si_4 public static void main(String args) int temp = 3;for (int i = 1; i <= temp; i+) f

10、or (int j = 1; j <= temp - i; j+) System.out.print(" ");for (int k = 1; k <= 2 * i + 1; k+) System.out.print("*");System.out.print('n');4_5 輸出圖形package student.xiaoqiao.day01;public class Si_5 public static void main(String args) int temp = 4;for (int i = 1; i <=

11、 temp; i+) for (int k = 1; k <= 5; k+) System.out.print("*");System.out.print('n');5. 判斷水仙花數(shù) 輸入一個3位數(shù)，判斷個位，十位與百位的3次方的和是否等于其本身，相等就是水仙花數(shù)package student.xiaoqiao.day01;import java.util.Scanner;public class Wu public static void main(String args) System.out.println("請輸入一個三位數(shù)&quo

12、t;);Scanner sc = new Scanner(System.in);int a = sc.nextInt();int b = a / 100;int c = (a / 10) % 10;int d = a % 10;if (a = b * b * b + c * c * c + d * d * d) System.out.println("此數(shù)是水仙花"); else System.out.println("此數(shù)不是水仙花");6. 輸入一個x和y，在輸入一個字符x, 當輸入的字符為+，輸出x與y的和，當輸入的字符為-，輸出x與y的差，當輸入

13、的字符為*，輸出x與y的積，當輸入的字符為/，輸出x與y的商.package student.xiaoqiao.day01;import java.util.Scanner;public class Liu public static void main(String args) System.out.println("請輸入一個加減乘除字符");Scanner sc=new Scanner(System.in);char c=sc.next().charAt(0);int x=4;int y=2;switch (c) case '+':System.out

14、.println("x+y="+(x+y);break;case '-':System.out.println("x-y="+(x-y);break;case '*':System.out.println("x*y="+(x*y);break;case '/':System.out.println("x/y="+(x/y);break;default:System.out.println("輸入的字符不合法！");break;7.求數(shù)列 0,1,2

15、,32 ,.,nn-1 的和 要求判斷n是否在0到10之間，如果不在提示重新輸入，for循環(huán) while循環(huán)，do while 都要寫一遍。7.1package student.xiaoqiao.day01;import java.util.Scanner;public class Qi public static void main(String args) System.out.println("請輸入一個0到10的數(shù)字");Scanner sc=new Scanner(System.in);int a=sc.nextInt();if (a>=0&a<

16、;=10) int b=0;for (int i = 1; i <=a; i+) b=(int) (b+Math.pow(i,i-1);System.out.println(b);else System.out.println("輸入的數(shù)不在0到10之間，請重新輸入！");7.2package student.xiaoqiao.day01;import java.util.Scanner;public class Qi_dowhile public static void main(String args) System.out.println("請輸入一個

17、0到10的數(shù)字");Scanner sc = new Scanner(System.in);int a = sc.nextInt();if (a>=0&a<=10) int b=0;int i=1; dob = (int) (b + Math.pow(i, i-1);i+;while (i<=a); System.out.println(b);else System.out.println("輸入的數(shù)不在0到10之間，請重新輸入！");7.3package student.xiaoqiao.day01;import java.util.S

18、canner;public class Qi_while public static void main(String args) System.out.println("請輸入一個0到10的數(shù)字");Scanner sc = new Scanner(System.in);int a = sc.nextInt();if (a>=0&a<=10) int b=0;int i=1; while (i<=a) b = (int) (b + Math.pow(i, i-1);i+; System.out.println(b);else System.out

19、.println("輸入的數(shù)不在0到10之間，請重新輸入！");8輸出9*9乘法表package student.xiaoqiao.day01;public class Ba public static void main(String args) for (int i = 1; i <=9; i+) for (int j = 1; j <=i; j+) System.out.print(i+"*"+j+"="+i*j+" ");System.out.print('n');9. 輸入x,

20、y比較大小，使用三目運算package student.xiaoqiao.day01;import java.util.Scanner;public class Jiu public static void main(String args) System.out.println("請輸入兩個值：");Scanner sc=new Scanner(System.in);int x=sc.nextInt();int y=sc.nextInt();System.out.println(x>y?"x大于y":"x小于y");Day02

21、作業(yè)題目：編寫程序實現(xiàn)一個猜數(shù)字游戲：系統(tǒng)隨機生成一個100以內(nèi)的整數(shù)，用戶根據(jù)系統(tǒng)提示來進行猜測，如果猜對，則顯示“恭喜”并提示“增加難度，需要繼續(xù)嗎？”，如果用戶選擇繼續(xù)則系統(tǒng)隨機生成一個1000以內(nèi)的整數(shù)，否則系統(tǒng)退出；如果用戶猜錯，則顯示“錯誤，請重新輸入！”，一旦用戶連續(xù)5次沒有猜中，則系統(tǒng)退出！package student.xiaoqiao.Day02;import java.util.Scanner;import java.util.concurrent.CountDownLatch;public class Randomdemo public static void main

22、(String args) int a=(int) (Math.random()*100)+1;/系統(tǒng)隨機生成一個1到100的整數(shù)System.out.println(a);System.out.println("請輸入一個1到100的整數(shù)");Scanner sc1=new Scanner(System.in);/從鍵盤上輸入一個數(shù)int num1=sc1.nextInt();while(num1!=a) if(num1>a)System.out.println("您輸入的數(shù)字過大，請重新輸入!");if(num1<a)System.out

23、.println("您輸入的數(shù)字過小，請重新輸入!"); num1=sc1.nextInt();if(num1=a) System.out.println("小主好棒,您猜對啦！"+'r'+"請問還要升級難度嗎（隨機生成1到1000的整數(shù)），繼續(xù)請輸入是，退出選擇否。"+'r');char ch=sc1.next().charAt(0);if (ch='是') int b=(int) (Math.random()*1000)+1;/系統(tǒng)隨機生成一個1到1000的整數(shù)System.out.

24、println(b);System.out.println("請輸入一個1到1000的整數(shù)");int num2=sc1.nextInt();int count=1;while(num2!=b&count<5) System.out.println("錯誤，請重新輸入!"); num2=sc1.nextInt(); count+; if (num2=b) System.out.println("您已輸入超過五次，游戲結束！");if (ch='否') System.out.println("游戲

25、結束！");4. 歌手找打分：在歌唱比賽中，共有10位評委進行打分，在計算歌手得分時，去掉一個最高分，去掉一個最低分，然后剩余的8位評委的分數(shù)進行平均，就是該選手的最終得分，輸入每個評委的評分，求某選手的得分。package student.xiaoqiao.Day02;import java.awt.peer.SystemTrayPeer;import java.util.Scanner;public class Grade public static void main(String args) int qiao =new int10;System.out.println(&qu

26、ot;請輸入十位評委成績(回車確認)：");Scanner scanner = new Scanner(System.in);for(int i=0;i<10;i+)qiaoi=scanner.nextInt();/if(i=9)/System.out.println("停止輸入！");/for (int i = 0; i < qiao.length; i+) for (int j = i + 1; j < qiao.length; j+) if (qiaoi < qiaoj) int temp = qiaoi;qiaoi = qiaoj;

27、qiaoj = temp;/System.out.print(qiaoi+" ");int sum = 0;for (int i = 1; i < 9; i+) sum = sum + qiaoi;System.out.println(sum / 8.0);-1. /* 字符串比較空間的里值，* 1、輸入89.9543 四舍五入 (1)保留2位 (2) 取整四舍五入-math方法package student.xiaoqiao.Day02;public class Yi_sishewuru public static void main(String args) do

28、uble a=89.9543;System.out.println(Math.round(a*100 )/100.0);System.out.println(Math.round(a); * 2、已經(jīng)字符串“this is a test of java” * （1）統(tǒng)計該字符串s出現(xiàn)的次數(shù) * （2）取出字符串中“test” * （3）將字符串中每個單詞的第1個字符，變成大寫輸出。 * （4）用兩種方式實現(xiàn)該字符串的倒敘輸出（用StringBuffer和for實現(xiàn)） * (5)算出字符串中字母、數(shù)字、空格各多少package student.xiaoqiao.Day02;public clas

29、s Er_Zifuchuan public static void main(String args) int count=0;String str="this is a test of java"for(int k=0;k<str.length();k+)String a1 = str.substring(k,k+1);if(a1.equals("s")count+;System.out.println(count);System.out.println(str.substring(10, 14);String a2=str.split(&quo

30、t; ");StringBuffer a4=new StringBuffer();for(int k=0;k<a2.length;k+)a4.append(a2k.substring(0, 1).toUpperCase()+a2k.substring(1)+" ");System.out.println(a4.toString();StringBuffer a5 = new StringBuffer(str);System.out.println(a5.reverse();for(int k=0;k<str.length();k+)System.out

31、.print(str.substring(str.length()-1-k,str.length()-k)+"");int englishCount=0;int spaceCount=0;int numCount=0;char aa=str.toCharArray(); for (int i = 0; i < aa.length; i+) if (Character.isLetter(aai) englishCount+;else if (Character.isSpaceChar(aai) spaceCount+;else if (Character.isDigit

32、(aai) numCount+;System.out.println();System.out.println("字母的個數(shù)："+englishCount);System.out.println("空格的個數(shù)："+spaceCount);System.out.println("數(shù)字的個數(shù)："+numCount); * 3、輸入某年某月某日，判斷這一天是這一年的第幾天(date)package student.xiaoqiao.Day02;/import java.text.SimpleDateFormat;/import java.u

33、til.Date;/public class San_Date /public static void main(String args) /Date d=new Date();/SimpleDateFormat sim=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");/String ss=sim.format(d);/System.out.println(ss);/import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Ca

34、lendar;import java.util.Date;import java.util.Scanner;public class San_Date public static void main(String args) try Scanner sc = new Scanner(System.in);System.out.print("輸入時間(格式:yyyy-MM-dd)");String str = sc.nextLine();SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");Date

35、 d = f.parse(str);Calendar c = Calendar.getInstance();c.setTime(d);System.out.println(str + "是這一年的第" + c.get(Calendar.DAY_OF_YEAR)+ "天"); catch (ParseException e) e.printStackTrace(); * 4、輸入3個數(shù)由小到大的排序import java.util.Scanner;public class Si_paixu public static void main(String ar

36、gs) System.out.println("請輸入三個數(shù)：");int qiao = new int3;Scanner scanner = new Scanner(System.in);for (int i = 0; i < 3; i+) qiaoi = scanner.nextInt();for (int i = 0; i < qiao.length; i+) for (int j = i + 1; j < qiao.length; j+) if (qiaoi > qiaoj) int temp = qiaoi;qiaoi = qiaoj;qi

37、aoj = temp;System.out.print(qiaoi + " "); * 5、編寫一個截取字符串的函數(shù)，輸入為一個字符串和字節(jié)數(shù)輸出為按字截取的字符串。但是要保證漢字不被截半個，如：“我ABC”4，應該截為“我AB”，輸入“我ABC漢DEF”6， * 應該輸出為“我ABC”，而不是ABC+漢的半個。（有點復雜可以先做別的） */package com.day02;public class Test05 public static void main(String args) / TODO Auto-generated method stubString ss

38、= getString("s我是DW", 4);/ 調用ss=getString("我ABC漢DEF",6);System.out.println(ss);/拼接/StringBuffer sss=new StringBuffer();/sss.append("akd");/sss.append(ss.charAt(0);public static String getString(String s, int n) int index = 0;/ 定義游標位置StringBuffer ss = new StringBuffer();/

39、 用來存放新的值for (int i = 0; i <= n - 1; i+) if (s.charAt(index) < 255 && s.charAt(index) > 0| Character.isDigit(s.charAt(index) / 如果當前字符是數(shù)字字符ss.append(s.charAt(index);/append:參數(shù)將被追加到此序列。此序列的長度將增加 1。index+; else / 如果當前字符是漢字if (index <= n - 2) / ss.append(s.charAt(index);/charAt(index)

40、返回指定索引處的 char 值。index+;n-;/ 當遇到漢字以后，因漢字占兩個字節(jié)，n自動減1，例如"s我"總共占3個字節(jié)，"n"代表所取字節(jié)數(shù)，這時候已經(jīng)占用了3個字節(jié)，當需要取2個/ 字節(jié)時,”s我“是點3個字節(jié)，"我"自動取消,當需要取4個字節(jié)時，”s我是“是占用5個字節(jié)，return ss.toString();6. 將十進制數(shù)35轉換為二進制數(shù)package student.xiaoqiao.Day03;public class Liu_shijinzhi public static void main(String

41、args) System.out.println(Integer.toBinaryString(35);7. 將字符串數(shù)組按字典的順序重新排列"Java","Basic ","C+"," Fortran","SmallTalk"package student.xiaoqiao.Day03;import java.util.Arrays;public class QI_paixu public static void main(String args) String s=new String5;s

42、0="Java"s1="Basic"s2="C+"s3="Fortran"s4="SmallTalk"Arrays.sort(s);System.out.println(Arrays.toString(s);8.輸出楊輝三角 效果圖如下package student.xiaoqiao.Day03;import java.util.Scanner;public class Ba_yanghui public static void main(String args) System.out.prin

43、tln("請輸入一個整數(shù)：");Scanner sc=new Scanner(System .in);int b=sc.nextInt();int a = new intbb; for (int i = 0; i < b; i+) aii = 1; ai0 = 1;for (int i = 2; i <b; i+) for (int j = 1; j < i; j+) aij = ai - 1j - 1 + ai - 1j;for (int i = 0; i <b; i+) /for (int k = 0; k < 2 * (2*b - i)

44、- 1; k+) /System.out.print(" ");/for (int j = 0; j <=i; j+) System.out.print(aij + " ");System.out.println();9（附加題）輸出N*N方陣N輸入為1時N輸入為2時。N輸入為5時/* * 2）、假設N=5,顯示5*5的方陣的轉圈結果 * 1 2 3 4 5 * 16 17 18 19 6 * 15 24 25 20 7 * 14 23 22 21 8 * 13 12 11 10 9 * * 1、判斷有多少個外循環(huán)， * 2、四個for循環(huán)輸出 *

45、/package com.day03Home;import java.util.Scanner;public class Test09 public static void main(String args) / TODO Auto-generated method stubint k=1;Scanner sc=new Scanner(System.in);System.out.print("請輸入N*N方陣的數(shù)為：");int N=sc.nextInt();int a=new intNN;for(int i=0;i<=N/2;i+)for(int j=i;j<

46、N-i;j+) /0-4 1-3 2-2aij=k+;for(int j=i+1;j<N-i;j+) /1-4 2-3ajN-i-1=k+;for(int j=N-i-2;j>=i;j-) /3-0 2-1aN-i-1j=k+;for(int j=N-i-2;j>i;j-) /3-1aji=k+;for(int i=0;i<a.length;i+)for(int j=0;j<a.length;j+)System.out.print(aij+"t");System.out.println();10.五子棋游戲11. 用遞歸來實現(xiàn)5！=5*4！=5

47、*4*3！=5*4*3*2！=5*4*3*2*1輸出5！的值package student.xiaoqiao.Day03;public class Shiyi_digui public static int fn(int n) if (n <= 1) return 1;else return n * fn(n - 1);public static void main(String args) System.out.println("5!="+fn(5);12. 0、1、1、2、3、5、8、13、21、34、在數(shù)學上，斐波納契數(shù)列以如下被以遞歸的方法定義：F（0）=0，

48、F（1）=1，F(xiàn)（n）=F(n-1)+F(n-2)（n2）package student.xiaoqiao.Day03;import java.util.Scanner;public class Shier_Fn public static int fn(int n)if (n=0) return 0;else if (n=1) return 1;else return fn(n-1)+fn(n-2);public static void main(String args) System.out.println("請輸入一個數(shù)：");Scanner scanner=new Scanner(System.in);int a=scanner.nextInt();System.out.println(fn(a);13. 1二分法.package student.xiaoqiao.Day04;import java.util.Scanner;public class Erfen public static void main(String args) int a = 1, 21, 25, 44