青島理工大學(xué)-實(shí)驗(yàn)2：類的封裝性和繼承性設(shè)計(jì)

1、課程實(shí)驗(yàn)報(bào)告課程 名稱java應(yīng)用技術(shù)班級計(jì)算112實(shí)驗(yàn)日期2013.9.26姓名學(xué)號實(shí)驗(yàn)成績實(shí)驗(yàn) 名稱實(shí)驗(yàn)2：類的封裝性和繼承性設(shè)計(jì)實(shí)驗(yàn)?zāi)康募耙?. 掌握java類的概念；2. 熟練運(yùn)用類的屬性和方法。實(shí) 驗(yàn) 環(huán) 境操作系統(tǒng):windowside： ecl ipse實(shí)驗(yàn)內(nèi)容（1）有理數(shù)四則運(yùn)算。編寫一個java應(yīng)用程序，實(shí)現(xiàn)兩個有理數(shù)的四則運(yùn)算，要求有理數(shù)用分子和分母的形 式表示。結(jié)果要求用“分子/分母”的形式表示。（2）表演最終得分。聲明一個average接口，英中約定求平均值的方法（參數(shù)為一個數(shù)組）；聲明first>second類實(shí)現(xiàn)average接口，分別給出求平均值的方法實(shí)現(xiàn)

2、。a. 類first +的功能為全部數(shù)值相加后求平均值。b. 類second中的功能為去掉一個最高分和一個最低分，再將總分求平均值。調(diào)試過程及實(shí)驗(yàn)結(jié)果1、規(guī)定數(shù)據(jù)的輸入格式必須在運(yùn)算符的兩邊加一個空格。解題思想:定義一個類:包含分子，分母屬性，和四則運(yùn)算的方法還有一個私有的方 法gcd（int, int）：求兩個整數(shù)的最大公約數(shù)。然后對輸入數(shù)據(jù)進(jìn)行處理分離出兩個操 作數(shù)，通過構(gòu)造器形成該類的對象，傳入類方法。請輸入兩個有理數(shù)的表達(dá)式,最后讀入運(yùn)算符（運(yùn)算符號兩邊各有一個空格）12/5 * 11/3the result is 44/5請輸入兩個有理數(shù)的表達(dá)式,最后讀入運(yùn)算符（運(yùn)算符號兩邊各有一個

3、空格）12 + 16/5|the result is 76/5請輸入兩個有理數(shù)的表達(dá)式,最后讀入運(yùn)算符（運(yùn)算符號兩邊各有一個空格）19/9 / 15/9the result is 19/15請輸入兩個有理數(shù)的表達(dá)式，最后讀入運(yùn)算符（運(yùn)算符號兩邊各有一個空格）1 - 15/8（the result is -7/8請輸入兩個有理數(shù)的表達(dá)式，最后讀入運(yùn)算符（運(yùn)算符號兩邊各有一個空格）15 - 45the result is -302、定義一個接口 average 請有一個方法:averge（double ）定義兩個類first,second分別事項(xiàng)average接口.英屮second自己實(shí)現(xiàn)一個私有

4、方法，用來把一組數(shù)據(jù)中的最高和最低分?jǐn)?shù)清零（前提是：分?jǐn)?shù)不能為零）請輸入一組分?jǐn)?shù)（s c o廠r ）123456789 10隹掉最高最低分后的平均數(shù)：5.0加權(quán)平均數(shù)：4.0睛輛人一紐分?jǐn)?shù)（.score；15.235 12.365 1.023 156.2 12.3|11.256 15.213 15.246 18.2365 15.265結(jié)果：去掉最高最低分后的平均數(shù)：14.0加權(quán)平均數(shù)：h.0總結(jié)實(shí)驗(yàn)的結(jié)果在普通的情況下，能夠計(jì)算出正確的結(jié)果。對于大數(shù)據(jù)可能會出現(xiàn)溢出的 結(jié)果。本次實(shí)驗(yàn)掌握了寫類的一些經(jīng)驗(yàn)，和類實(shí)現(xiàn)接口的經(jīng)驗(yàn)。附 錄1、import java.util. seanner;impo

5、rt java.lang.exception;import java. iang. numberformatexception;public class algrithm private long fenzi=0;private long fenmu=0;public algrithmo /構(gòu)造器pub lie algr it hm(long fen zi, long fen mu) /構(gòu)造器long x = ged(fenzi, fenmu);this, fenzi = (fenzi/x);this, fenmu = (fenmu/x);private static long gcd(lon

6、g n, long m) /返回最大公約數(shù)long r=n%m;while(r != 0) n 二 m;m=r;r二;return m;private long getfenzi () /取分子return fenzi;private long getfenniuo /取分目return fenmu;publie static algrithmadd(algrithm addend, algrithm augend)throws exceptioni/求加與被加數(shù)分母的乘積long product = addend, getfenmu() * augend. getfenmu();/adden

7、d分子與augend分母的乘積long addproduct = addend. getfen/i() * augend. geteenmu();/augend的分子與addend的分母的乘積long augproduct = augend. getfenzi () * addend. getfenmu(); long greatestdivisor = ged(addproduct+augproduct, product); returnnewalgrithm(addproduct+augproduct)/greatestdivisor, product/greatestdivisor);/

8、被減數(shù)減數(shù)public static algrithmsubtraction(algrithm minuend , algrithm subtrahend ) /求減與被減數(shù)分母的乘積long product = minuendgetfenmu() subtrahend. getfenmuo ;/求minuend分子與subtrhend的分母的乘積long minproduct = minuend. getfentsi ()*subtrahend getfenmu();/求subtrahend分子與minuend的分母的乘積long subproduct = subtrahend. getfe

9、nzi () * minuend. getfenmu();long greatestdivisor = ged(minproduct - subproduct), product); returnnewalgri thm (mi nproductsubproduct)/greatestdivisor, product/greatestdivisor);public static algrithmmultil (algrithm multiplicand , algrithm multiplier) /計(jì)算multiplicand分母的乘積和multiplier的分母的乘積long produc

10、t = multiplicand, getfenmu()*mul tipi ier. getfenmu();/計(jì)算multiplicand的分子和multiplier的分子的乘積long otherproduct =multiplicand. getfenzi () * multiplier. getfenzi ();long greatestdivisor =ged (product, otherproduct);product =product/greatestdivisor;otherproduct =otherproduct/greatestdi vi sor;return new a

11、lgrithm(otherproduct, product);public static algrithmdivision(algrithm dividend, algrithm divisor) /計(jì)算dividend的分子和divisor的分母的乘積long product = dividendgetfenzi () * divisor. getfenmu ();/計(jì)算dividend的分母和divisor的分子的乘積long otherproduct = dividendgetfenmu () * divisor.getfenzi (); long greatestdivisor =gc

12、d(product, otherproduct);product = product/greatestdivisor;otherproduct = otherproduct/greatestdivisor;return now algrithm(product,otherproduct);publ ic void palyo /顯示有理數(shù)system out. print(the result is “)；systemout. print (thisfenzi );if (this. fenmu != 1)system. out> print in (，/， + +this. fenmu

13、);/* param args*/public static void main(string args) throws exceptionisystem, out. print in ("請輸入兩個有理數(shù)的表達(dá)式，最后讀入運(yùn)算符(運(yùn)算符號兩邊各有一個空格)；scanner read = new scanner (system, in) ;/讀入表達(dá)式字符串iong number = new iong4;string expr = read.nextline ();expr. trim();int index = expr. indexof (，);int t二index;/提供給笫

14、二個操作數(shù)使用string first = expr substring(0, index);/system, outprintln(first： " + first);string shenyu = exprsubstring(index+l); shenyu = shenyu. trim() ;/去掉兩頭的空格 /system, outprintin("shenyu:" + shenyu);char fuhao = shenyu. charat (0);index = shenyu. indexof ('');/剩下的字符串/system, o

15、utprintln(index: + index);string second = shenyu. substring(index +1);seco nd = seco nd. trim();/system, out. pr in tin (，zseco nd: + second);/對第一個操作數(shù)進(jìn)行處理index = first, indexof ('/');if(index = -1)number0=long parselong(first);number1=1;elsenumber0=long. parselong(first, substring(0, index);

16、int length = first.length ();numberl=long parselong(first. substring(index+1, length);/對第二個操作數(shù)進(jìn)行處理index = second. indexof(');if(index = -1) number2=long. parselong (second);number3=1;else number2=long. parselong(second. substring(0, index);number3=long parselong(second, substring(index+l, second

17、. length();algrithm x = now algrithm(number0, number1);algrithm y = new algrithm(number2, number3); switch(fuhao) case ': algrithm. division(x, y). paly 0;break; case:algrithmmultil(x, y ) paly() ;break;case ':algrithm subtraction(x, y). paly();break;case ' +' :algrithm. add(x, y). p

18、aly () ;break; default :break;2、/接口public interface average public abstract double average(double array); /first類public class first implements average public double average(double array) int sum=0;for(int i=0 ; i<array.length;i+) sum+=arrayi;return sum/array.length;import java utilseanner;public class second implements average private void did(double x) doubl