软件工程个人作业01

（已改编为网页版）

程序设计思想：

创建表达式类Expression、运算数类RationalNumber、表达式随机生成器类ExpressionRandom、表达式组成元素类Element

每个Element由一个运算数(RationalNumber) + 一个运算符(String)构成

对每一个表达式，按照以下规则将其拆分：

如表达式“2+3-4/7

 一个运算数+一个运算符作为一个元素(Element，详见Element.java)，如即2+、3-

每个表达式为2个或三个Element构成的列表(List)，最后一个元素(Element)没有跟着的运算符，补充"#"即表达式“2+3-4/7”由一个列表{2+、3-、4/7#}表示。

源程序代码：

RationalNumber.java

/*******运算数类*******/

package model;
public class RationalNumber {
    private int denominator;    //分母
    private int numerator;        //分子
    
    /***构造函数，整数看做分母为1的分数***/
    public RationalNumber(int numerator) {
        this.numerator = numerator;
        denominator = 1;
    }
    /****构造函数，第一个参数为分子，第二个为分母****/
    public RationalNumber(int numerator,int denominator) {
        this.denominator = denominator;
        this.numerator = numerator;
    }
    public int getDenominator() {
        return denominator;
    }
    public void setDenominator(int denominator) {
        this.denominator = denominator;
    }
    public int getNumerator() {
        return numerator;
    }
    public void setNumerator(int numerator) {
        this.numerator = numerator;
    }
    
    /***判断两个分数是否相等***/
    @Override
    public boolean equals(Object obj) {
        // TODO Auto-generated method stub
        RationalNumber rn = (RationalNumber)obj;
        if(this.denominator == rn.denominator && this.numerator == rn.numerator) {
            return true;
        }else return false;
    }
    
    /*****分数相加*****/
    public RationalNumber plus(RationalNumber rb) {
        int addNum1 = this.numerator * rb.denominator;
        int addNum2 = rb.numerator * this.denominator;
        int demo = this.denominator * rb.denominator;
        RationalNumber value = new RationalNumber(addNum1 + addNum2,demo);
        value.simply();
        return value;
    }
    
    /*****分数相减*****/
    public RationalNumber minus(RationalNumber rb) {
        int addNum1 = this.numerator * rb.denominator;
        int addNum2 = rb.numerator * this.denominator;
        int demo = this.denominator * rb.denominator;
        RationalNumber value = new RationalNumber(addNum1 - addNum2,demo);
        value.simply();
        return value;
    }
    
    /*****分数相乘*****/
    public RationalNumber multiply(RationalNumber rb) {
        RationalNumber value = new RationalNumber(this.numerator * rb.numerator,this.denominator * rb.denominator);
        value.simply();
        return value;
    }
    
    /*****分数相除*****/
    public RationalNumber divide(RationalNumber rb) {
        RationalNumber value = new RationalNumber(this.numerator * rb.denominator,this.denominator * rb.numerator);
        value.simply();
        return value;
    }
    
    /*****分数化简*****/
    public void simply() {
        if(numerator == 0) {
            denominator = 1;
            return ;
        }
        
        int small,big,temp;
        if(numerator > denominator) {
            small = denominator;
            big = numerator;
        }else {
            big = denominator;
            small = numerator;
        }
        while(small != 0) {
            temp = big % small;
            big = small;
            small = temp;
        }
        numerator /= big;
        denominator /= big;
    }
    
    /****取得字符串****/
    @Override
    public String toString() {
        if(denominator == 1)
            return String.valueOf(numerator);
        else return String.valueOf(numerator + "/" + denominator);
    }
    
    /****取得Html格式字符串****/
    public String toHtmlDiv() {
        String str = null;
        if(denominator == 1)
            str = "<div class='nomal'>" + this.numerator + "</div>";
        else
            str = "<div class='fraction'><div>" + this.numerator + "</div><div style='border-top:2px solid black;'>" + this.denominator + "</div></div>";
        return str;
    }
}

/**每个Element由一个运算数(RationalNumber) + 一个运算符(String)构成：
 * 具体代码如下：
 */

package model;

public class Element{
    
    RationalNumber fraction;            //运算数
    String operator;                    //运算符
    //构造方法
    public Element(RationalNumber fraction, String operator) {
        this.fraction = fraction;
        this.operator = operator;
    }
    //运算数的get/set方法
    public RationalNumber getFraction() {
        return fraction;
    }
    public void setFraction(RationalNumber fraction) {
        this.fraction = fraction;
    }
    //运算符的get/set方法
    public String getOperator() {
        return operator;
    }
    public void setOperator(String operator) {
        this.operator = operator;
    }
    //重载equals方法，判读两个元素是否相同
    @Override
    public boolean equals(Object obj) {
        Element element = (Element)obj;
        if(this.fraction.equals(element) && this.operator.equals(element.operator))
            return true;
        else return false;
    }
    
    
}

Expression.java

/**对每一个表达式，按照以下规则将其拆分：
 * 如表达式“2+3-4/7”
 * 一个运算数+一个运算符作为一个元素(Element，详见Element.java)，如即2+、3-
 * 每个表达式为2个或三个Element构成的列表(List)，
 * 最后一个元素(Element)没有跟着的运算符，补充"#"
 * 
 * 即表达式“2+3-4/7”由一个列表{2+、3-、4/7#}表示。
 */

package model;

import java.util.List;

public class Expression {
    private List<Element> expr;                    //Element构成的列表，表示一个表达式
    
    public Expression(List<Element> expr) {        //构造方法，参数为List<Element>类型
        this.expr = expr;
    }

    //表达式列表的get/set方法
    public List<Element> getExpr() {
        return expr;
    }

    public void setExpr(List<Element> expr) {
        this.expr = expr;
    }

    //得到表达式字符串,如"1+2/4/7"
    @Override
    public String toString() {
        String exprStr = new String();
        for(Element e:expr) {
            exprStr += e.getFraction().toString();
            if(!e.getOperator().equals("#"))
                exprStr += e.getOperator();
        }
        return exprStr;
    }

    /****取得Html格式字符串
     * 如"<div class='nomal'>7</div><div class='nomal'>×</div><div class='nomal'>1</div><div class='nomal'>+</div><div class='nomal'>86</div><div class="nomal">=</div>"
     * 在html中直接加入toHtmlDiv()生成的字符串，可规范显示该表达式
     */
    public String toHtmlDiv() {
        String exprStr = new String();
        for(Element e:expr) {            //将每个元素转为html格式div，详见Element.java
            exprStr += e.getFraction().toHtmlDiv();
            if(!e.getOperator().equals("#"))
            {
                //存运算符时以"*、/"表示乘除运算符，此处转换为"×、÷"
                if(e.getOperator().equals("*"))
                    exprStr += "<div class='nomal'>×</div>";
                else if(e.getOperator().equals("/"))
                    exprStr += "<div class='nomal'>÷</div>";
                else
                    exprStr += "<div class='nomal'>"+ e.getOperator() + "</div>";
            }
        }
        exprStr += "<div class="nomal">=</div>";
        System.out.println(exprStr);
        return exprStr;
    }
    
    /****两个算数表达式是否相同****/
    @Override
    public boolean equals(Object obj) {
        Expression expr = (Expression)obj;
        if(this.expr.size() != expr.expr.size())
            return false;
        for(int i = 0;i < this.expr.size();i++)
        {
            if(!this.expr.get(i).equals(expr.expr.get(i)))
                return false;
        }
        return true;
    }
    
    /****计算结果，表达式不合法时，返回null****/
    public RationalNumber getResult() {
        RationalNumber rn = null;                //结果
        int length = this.getExpr().size();        //运算数个数
        String op1 = this.getExpr().get(0).operator,op2;        //第1、2个运算符
        if(length == 2)                            //二元运算
            rn = calc(this.getExpr().get(0).fraction,op1,this.getExpr().get(1).fraction);
        else {
            op2 = this.getExpr().get(1).operator;
            RationalNumber rn_temp;                //中间数
            //运算符优先级判断
            if((op1.equals("+") || op1.equals("-"))&&(op2.equals("*")||op2.equals("/"))){
                rn_temp = calc(this.getExpr().get(1).fraction,op2,this.getExpr().get(2).fraction);
                if(rn_temp == null)return null;
                //if(rn_temp == null || rn_temp.getDenominator() > 100 || rn_temp.getNumerator() > 100 || rn_temp.getDenominator() < 0 || rn_temp.getNumerator() < 0 || rn_temp.getDenominator() == 0|| (rn_temp.getDenominator() != 1 && rn_temp.getNumerator() >= rn_temp.getDenominator())) return null;
                rn = calc(this.getExpr().get(0).fraction,op1,rn_temp);
            }else {
                rn = calc(this.getExpr().get(0).fraction,op1,this.getExpr().get(1).fraction);
                if(rn == null)return null;
                rn = calc(rn,op2,this.getExpr().get(2).fraction);
            }
        }
        
        if(rn == null || rn.getDenominator() > 100 || rn.getNumerator() > 100 || rn.getDenominator() < 0 || rn.getNumerator() < 0 || rn.getDenominator() == 0|| (rn.getDenominator() != 1 && rn.getNumerator() >= rn.getDenominator()))
            return null;
        else
            return rn;
    }
    
    /****根据单个运算符计算单个结果***/
    private RationalNumber calc(RationalNumber rn1,String o,RationalNumber rn2) {
        RationalNumber rn = null;
        if(rn1.getDenominator() > 100 || rn1.getNumerator() > 100 || rn1.getDenominator() < 0 || rn1.getNumerator() < 0 || rn1.getDenominator() == 0|| (rn1.getDenominator() != 1 && rn1.getNumerator() >= rn1.getDenominator()) || rn2.getDenominator() > 100 || rn2.getNumerator() > 100 || rn2.getDenominator() < 0 || rn2.getNumerator() < 0 || rn2.getDenominator() == 0 || (rn2.getDenominator() != 1 && rn2.getNumerator() >= rn2.getDenominator())){
            rn = null;
        }else {
            if(o.equals("+"))
                rn = rn1.plus(rn2);
            else if(o.equals("-"))
                rn = rn1.minus(rn2);
            else if(o.equals("*"))
                rn = rn1.multiply(rn2);
            else if(o.equals("/"))
            {
                if(rn2.getNumerator() != 0)
                    rn = rn1.divide(rn2);
                else return null;
            }
        }
        return rn;
    }
}

ExpressionRandom.java

/******题目（也称为运算表达式）随机生成器*****/

package model;

import java.util.ArrayList;
import java.util.List;

public class ExpressionRandom {
    /***定义运算符****/
    private static String[] operator = {"+","-","*","/"};
    
    /****随机得到一个表达式，elementNum为元素个数，isFraction表示是否支持分数计算*****/
    public static Expression getExpression(int elementNum,boolean isFraction) {
        /***表达式列表***/
        List<Element> expr = new ArrayList<Element>();
        int i,nume,demo;        //循环变量，分子，分母
        /***随机生成elementNum个Element(随机分数 + 运算符)，并添加到expr***/
        for(i = 0;i < elementNum;i++) {
            nume = (int) (Math.random() * 101);
            if(isFraction)
                demo = (int) (Math.random() * 100 + 1);        //分母不能为0
            else demo = 1;
            String oper = operator[(int)(Math.random() * 4)];
            RationalNumber rb = new RationalNumber(nume,demo);
            rb.simply();
            expr.add(new Element(rb,oper));
        }
        expr.get(i-1).setOperator("#");
        /****通过expr构造运算表达式，并返回****/
        return new Expression(expr);
    }
    
    /****得到经过过滤的表达式*****/
    public static Expression getValidExpression(int elementNum,boolean isFraction) {
        Expression expr = null;
        do {
            expr = getExpression(elementNum,isFraction);
        }while(expr.getResult() == null);                //（当表达式不合法时，返回计算结果为null）
        return expr;
    }
    
    /******测试主函数********/
    public static void main(String[] args) {
        for(int i = 0;i < 100;) {
            Expression expr = ExpressionRandom.getExpression(2, true);
            if(expr.getResult() != null) {
                System.out.println(expr.toString() + "=" + expr.getResult() + "
");
                i++;
            }
        }
    }
}

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<link rel="stylesheet" href="css/style.css"/>
<title>小学生四则运算</title>

</head>
<body>
<img alt="asdfsadf" src="img/pdf.png">
    <form action="arithmetic.jsp" class="option">
        <center><h2>题目定制</h2></center>
        <p>请选择题目类型：
            <select name="elementNum">
                <option>2</option>
                <option>3</option>
            </select>元运算<br /></p>
        题目数量：
                <input name="count" value="10" type="radio" />10
                <input name="count" value="20" type="radio" />20
                <input name="count" value="30" type="radio" />30
                <input name="count" value="40" type="radio" />40
                <input name="count" value="50" type="radio" />50
                <input name="count" value="60" type="radio" />60<br/>
                <input name="count" value="1000000" type="radio" />10000000(极限测试，慎选！！)
            <br /><br />
            <input type="checkbox" name="fraction" /><label>分数计算</label>
        <br />
        <button class="submit" style="margin-top:50px">开始答题！</button>
    </form>
</body>
</html>

arithmetic.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@page import="model.*" 
    import="java.util.List"
    import="java.util.ArrayList"%>
<%ExpressionRandom exprRand = new ExpressionRandom(); %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>小学生算数</title>
        <link rel="stylesheet" type="text/css" href="css/style.css"/>
        <script type="text/javascript" src="js/jquery-2.1.0.js" ></script>
        <script type="text/javascript" src="js/demo.js" ></script>
    </head>
    <body>
    
    <%
        //题目数量
        String str = request.getParameter("count");
    
        int count = 0;                        //题目数量
        int elementNum = 0;                    //运算数个数
        boolean isFraction = false;            //分数计算
        List<Expression> exprs = new ArrayList<Expression>();    //题目
        if(str != null){                    //判断是由用户定制题目页面跳转至该页面
            count = Integer.parseInt(str);
            elementNum = Integer.parseInt(request.getParameter("elementNum"));
            isFraction = (request.getParameter("fraction") != null);
            for(int i = 0;i < count;i++){
                exprs.add(ExpressionRandom.getValidExpression(elementNum, isFraction));
                //out.println(exprs.get(i).toString());
            }
            session.setAttribute("exprs", exprs);
        }else{
            
        }
    %>
    <form action="result.jsp">
        <table class="box" align="center" border="0" cellspacing="10" cellpadding="10">
    <%for(int i = 0;i < count;i+=2){%>
            <tr>
                <td align="center" class='expr'>
                    <%=exprs.get(i).toHtmlDiv()%>
                </td>
                <td><input autocomplete="off" value="" class="result" name="result" type="text"/></td>
                <td align="center" class='expr'>
                    <%=exprs.get(i + 1).toHtmlDiv()%>
                </td>
                <td><input autocomplete="off" value="" class="result" name="result" type="text"/></td>
            </tr>
        <%} %>
            <tr>
                <td colspan="4" align="center"><button class="submit">提交</button></td>
            </tr>
        </table>
        <input name="time" class="timer" type="text" />
    </form>
    </body>
</html>

result.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@page import="model.*" 
    import="java.util.List"
    import="java.util.ArrayList"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>结果</title>
<link rel="stylesheet" type="text/css" href="css/style.css"/>
</head>
<body>
<% List<Expression> exprs =(List<Expression>) session.getAttribute("exprs");        //题目
    String[] result = request.getParameterValues("result");    //用户答案
    int right = 0,i = 0;
    for(String re:result){
        re = re.trim();            //去除两端空格
        if(re.equals(exprs.get(i).getResult().toString()))
            right++;
        i++;
    }
    /*for(i = 0;i < exprs.size();i++){
        System.out.println(result[i]+"-------"+exprs.get(i).getResult());
        if(result[i].equals(exprs.get(i).getResult()))
            right++;
        i++;
    }*/
    
    %>
    <table class="box" align="center" border="0" cellspacing="10" cellpadding="10">
        <tr>
            <td colspan="6">你共答对了<%=right %>道题，答错<%=exprs.size()-right %>道题，得分:<%=(double)right/exprs.size() * 100 %>，用时：<%=request.getParameter("time") %></td>
        </tr>
        <%for(i = 0;i < exprs.size();i+=2){%>
            <tr>
                <td align="center" class='expr'>
                    <%=exprs.get(i).toHtmlDiv()%>
                </td>
                <td><input disabled="disabled" value="<%=result[i] %>" class="result" name="result" type="text"/></td>
                <%
                if(exprs.get(i).getResult().toString().equals(result[i])){
                %>
                    <td>√</td>
                <%
                }else{
                %>
                    <td>×&nbsp;&nbsp;正确答案：<%=exprs.get(i).getResult() %></td>
                <%    
                }
                %>
                <td align="center" class='expr'>
                    <%=exprs.get(i + 1).toHtmlDiv()%>
                </td>
                <td><input disabled="disabled" value="<%=result[i+1] %>" class="result" name="result" type="text"/></td>
                <%
                if(exprs.get(i + 1).getResult().toString().equals(result[i + 1])){
                %>
                    <td>√</td>
                <%
                }else{
                %>
                    <td>×&nbsp;&nbsp;正确答案：<%=exprs.get(i + 1).getResult() %></td>
                <%    
                }
                %>
            </tr>
        <%} %>
            <tr>
                <td colspan="6" align="center"><button class="submit" onClick="history.go(-1)">返回</button></td>
            </tr>
    </table>
</body>
</html>

运行结果截图：

上课未按时完成的原因：未能迅速理清思路。