四则运算题目生成程序
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定义： 自然数：0, 1, 2, …。 真分数：1/2, 1/3, 2/3, 1/4, 1’1/2, …。 运算符：+, −, ×, ÷。 括号：(, )。 等号：=。 分隔符：空格（用于四则运算符和等号前后）。 算术表达式： e := n | e1 + e2 | e1 − e2 | e1 × e2 | e1 ÷ e2 | (e), 其中e, e1和e2为表达式，n为自然数或真分数。 四则运算题目：e = ，其中e为算术表达式。
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功能：
1.生成随机数n
2.生成随机运算符
3.组成算数表达式
4.计算题目结果并输出文档
5.比较答案并给出错误题号
要求：
1.表达式不重复
2.结果无负数
3.结果最简
4.算符不超过三个
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1.生成表达式
2.求逆波兰式
3.计算逆波兰式
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import java.util.ArrayList; import java.util.List; import java.util.Random; public class FormulaMake { int range; //最大运算数的范围 int mount; //运算数的个数 //构造函数 public FormulaMake(int range, int mount) { super(); this.range = range; this.mount = mount; } //返回两个数的最大公约数（测试通过） public int greatestCommonDivisor(int m,int n) { int temp,i; int theDivisor=0; if(m<n) { temp = m; m = n; n = temp; } for(i=n;i>0;i--) { if((m%i==0)&&(n%i==0)) { theDivisor=i; break; } } return theDivisor; } //数字生成 public String createNum(int theRange) { theRange = getRange(); NPR npr = new NPR(); String theNumber = ""; int numerator; //分子 int denominator; //分母 numerator = (int)(Math.random()*theRange)+1; denominator = (int)(Math.random()*theRange)+1; theNumber=npr.simpleNum(numerator, denominator); return theNumber; }
//随机生成含有n个数字的四则运算算式 public List fourArithmetic(int element) { int n = 0; String[] operatorArray = new String[] {"+","-","*","÷"};//存储运算符的数组 element = getMount(); //运算元数，随机生成2到6个运算元 List arithmeticArray = new ArrayList(); //存储数字和四则运算符的集合 while(n<element) { String theNum = createNum(getRange()); arithmeticArray.add(theNum); int theIndex = (int)(Math.random()*4); //运算符数组指针{0,1,2,3} arithmeticArray.add(operatorArray[theIndex]); n++; } //生成不带括号的表达式 int theLast = arithmeticArray.size()-1; //最后一个多出来的符号的指针 arithmeticArray.remove(theLast); //生成带括号的表达式 boolean flag = false; int probability = (int)(Math.random()*5)+1; //生成括号的概率 if(probability>3) { //定义生成括号的概率为40% int theTemp = element-1; int insertPosition = (int)(Math.random()*theTemp);//插入左括号的合法位置 int leftInsertPosition = insertPosition*2; arithmeticArray.add(leftInsertPosition,"("); flag = true; //说明生成了左括号
//插入右括号 int tempLeft = arithmeticArray.indexOf("("); if((tempLeft+4) != arithmeticArray.size()) { int tempAdd = (int)(Math.random()*2); tempAdd+=2; int tempRight = tempLeft+(tempAdd*2); arithmeticArray.add(tempRight,")"); }else { arithmeticArray.add(arithmeticArray.size(),")"); } } return arithmeticArray; } //get set方法 public int getRange() { return range; } public void setRange(int range) { this.range = range; } public int getMount() { return mount; } public void setMount(int mount) { this.mount = mount; } }逆波兰式的转换：
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import java.util.ArrayList; import java.util.HashMap; import java.util.List; public class NPR { //查重用字符串 String CheckTheSame=""; public String getFindTheSame() { return CheckTheSame; } public void setFindTheSame(String findTheSame) { this.CheckTheSame = findTheSame; } //判断ch是否为运算符 public boolean inOp(char c){ if (c == '(' || c == ')' || c == '+' || c == '-' || c == '*' || c == '÷'){ return true; } else{ return false; } } //判断ch是否为运算符 public int precede(int op1,int op2){ if (op1 == op2){ return 0; } else if (op1 < op2){ return -1; } else{ return 1; } } //返回两个数的最大公约数（测试通过） public int greatestCommonDivisor(int m,int n) { int temp,i; int theDivisor=0; if(m<n) { temp = m; m = n; n = temp; } for(i=n;i>0;i--) { if((m%i==0)&&(n%i==0)) { theDivisor=i; break; } } return theDivisor; } //返回两个数的最小公倍数(测试通过) public int minTimes(int x,int y) { int temp=0; int theTimes=0; if(x<y) { temp = x; x = y; y = temp; } for(int i=x;i<=(x*y);i++) { if((i%x==0)&&(i%y==0)) { theTimes=i; break; } } return theTimes; } //数字化简 public String simpleNum(int numerator,int denominator) { String theNumber = ""; if(denominator==0) { System.exit(0); } if(numerator%denominator==0) { theNumber+=(numerator/denominator); }else { if(numerator<denominator) { int maxFactor = greatestCommonDivisor(numerator,denominator); if(maxFactor==0) { theNumber+=0; }else { int tempNumerator = numerator/maxFactor; int tempDenominator = denominator/maxFactor; theNumber+=tempNumerator+"/"+tempDenominator; } }else { int theMod = numerator%denominator; int theTimes = numerator/denominator; int maxFactor = greatestCommonDivisor(theMod,denominator); if(maxFactor==0) { theNumber+=0; }else { theMod = theMod/maxFactor; denominator = denominator/maxFactor; theNumber+=theTimes+"\'"+theMod+"/"+denominator; } } } return theNumber; } //逆波兰式 public List exchangeNPR(String formula) { //用哈希键值对映射左运算符的优先级 HashMap<String, Integer> lpri = new HashMap<String,Integer>(); lpri.put("=",0); lpri.put("(",1); lpri.put("*",5); lpri.put("÷",5); lpri.put("+",3); lpri.put("-",3); lpri.put(")",6); //用哈希键值对映射右运算符的优先级 HashMap<String, Integer> rpri = new HashMap<String,Integer>(); rpri.put("=",0); rpri.put("(",6); rpri.put("*",4); rpri.put("÷",4); rpri.put("+",2); rpri.put("-",2); rpri.put(")",1); //创建栈 Stack op = new Stack(); op.data = new char[200]; op.top=-1; op.top++; op.data[op.top]='='; //把传入的表达式转化成字符数组 char[] exp = formula.toCharArray(); //用来存储后缀表达式 List postexp = new ArrayList(); int j=0; while(j<exp.length) { if(!inOp(exp[j])) { while(j<exp.length&&((exp[j]>='0'&& exp[j]<='9')||(exp[j]=='\'')||(exp[j]=='/'))) { postexp.add(exp[j]); j++; } postexp.add('#'); }else { switch(precede(lpri.get(op.data[op.top]+""),rpri.get(exp[j]+""))){ case -1: op.top++; op.data[op.top]=exp[j]; j++; break; case 0: op.top--; j++; break; case 1: postexp.add(op.data[op.top]); op.top--; break; } } } while(op.data[op.top]!='=') { postexp.add(op.data[op.top]); op.top--; } return postexp; } //把运算数转换成数组{分子，分母} public int[] numberChangeArr(String number){ int num[] = new int[2]; if(number.indexOf('/')!=-1) { if(number.indexOf('\'')!=-1) { int theTimes = Integer.parseInt(number.split("\'")[0]); int numerator = Integer.parseInt((number.split("\'")[1]).split("/")[0]); int denominator = Integer.parseInt((number.split("\'")[1]).split("/")[1]); num[0] = theTimes*denominator+numerator; num[1] = denominator; }else { num[0] = Integer.parseInt(number.split("/")[0]); num[1] = Integer.parseInt(number.split("/")[1]); } }else { num[0] = Integer.parseInt(number); num[1] = 1; } return num; } //后缀表达式的计算 public String compvalue(String nprFormula) { Stack st = new Stack(); st.top=-1; st.data2 = new String[200]; int i=0; char[] postexp = nprFormula.toCharArray(); while(i<postexp.length) { switch(postexp[i]) { case '+': String a = st.data2[st.top]; st.top--; String b = st.data2[st.top]; st.top--; String c = ""; int numeratorA = numberChangeArr(a)[0]; int denominatorA = numberChangeArr(a)[1]; int numeratorB = numberChangeArr(b)[0]; int denominatorB = numberChangeArr(b)[1]; int theMinTimes = minTimes(denominatorA,denominatorB); numeratorA=(theMinTimes/denominatorA)*numeratorA; numeratorB=(theMinTimes/denominatorB)*numeratorB; int theAdd = numeratorA+numeratorB; c+=simpleNum(theAdd,theMinTimes); st.top++; st.data2[st.top]=c; break; case '-': String a2 = st.data2[st.top]; st.top--; String b2 = st.data2[st.top]; st.top--; String c2 = ""; int numeratorA2 = numberChangeArr(a2)[0]; int denominatorA2 = numberChangeArr(a2)[1]; int numeratorB2 = numberChangeArr(b2)[0]; int denominatorB2 = numberChangeArr(b2)[1]; int theMinTimes2 = minTimes(denominatorA2,denominatorB2); int theReduct = 0; theReduct = numeratorB2-numeratorA2; numeratorA2=(theMinTimes2/denominatorA2)*numeratorA2; numeratorB2=(theMinTimes2/denominatorB2)*numeratorB2; theReduct = numeratorB2-numeratorA2; if(theReduct==0) { c2+="0"; }else if(theReduct>0) { c2+=simpleNum(theReduct,theMinTimes2); }else { theReduct=Math.abs(theReduct); c2+="-"+simpleNum(theReduct,theMinTimes2); } st.top++; st.data2[st.top]=c2; break; case '÷': String a3 = st.data2[st.top]; st.top--; String b3 = st.data2[st.top]; st.top--; String c3 = ""; int numeratorA3 = numberChangeArr(a3)[0]; int denominatorA3 = numberChangeArr(a3)[1]; int numeratorB3 = numberChangeArr(b3)[0]; int denominatorB3 = numberChangeArr(b3)[1]; if(numeratorA3!=0) { int theNumerator = numeratorB3*denominatorA3; int theDenominator = denominatorB3*numeratorA3; c3 += simpleNum(theNumerator,theDenominator); st.top++; st.data2[st.top]=c3; }else { System.exit(0); } break; case '*': String a4 = st.data2[st.top]; st.top--; String b4 = st.data2[st.top]; st.top--; String c4 = ""; int numeratorA4 = numberChangeArr(a4)[0]; int denominatorA4 = numberChangeArr(a4)[1]; int numeratorB4 = numberChangeArr(b4)[0]; int denominatorB4 = numberChangeArr(b4)[1]; int numerator = numeratorA4*numeratorB4; int denominator = denominatorA4*denominatorB4; c4+=simpleNum(numerator,denominator); st.top++; st.data2[st.top]=c4; break; default: String d = ""; while((postexp[i]>='0'&&postexp[i]<='9')||(postexp[i]=='\'')||(postexp[i]=='/')) { d+=postexp[i]; i++; } st.top++; st.data2[st.top]=d; break; } i++; } return st.data2[st.top]; } }
| PSP2.1 | Personal Software Process Stages | Time Senior Student | Time | |
| Planning | 计划 | 8 | 8 | |
| · Estimate | 估计这个任务需要多少时间 | 8 | 9 | |
| Development | 开发 | 1 | 1 | |
| · Analysis | 需求分析 (包括学习新技术) | 0.5 | 0.5 | |
| · Design Spec | 生成设计文档 | 0.2 | 0.2 | |
| · Design Review | 设计复审 | 1 | 2 | |
| · Coding Standard | 代码规范 | 0.1 | 0.15 | |
| · Design | 具体设计 | 0.5 | 0.5 | |
| · Coding | 具体编码 | 0.5 | 0.5 | |
| · Code Review | 代码复审 | 0.5 | 0.5 | |
| · Test | 测试（自我测试，修改代码，提交修改） | 0.5 | 05 | |
| Reporting | 报告 | 0.1 | 0.1 | |
| · | 测试报告 | 0.1 | 0.1 | |
| · | 计算工作量 | 0.1 | 0.1 | |
| · | 并提出过程改进计划 | 0.1 | 0.1 | |
