(I) effect display
Item bank XX.txt
Answer process
Storage record file xx.txt
(2) encapsulate the required +, -, and other symbols, and then write several judgment methods
1 public char[] op = {'+','-','*','/','(',')'}; 2 public String[] strOp = {"+","-","*","/","(",")"}; 3 public boolean isDigit(char c){ 4 if(c>='0'&&c<='9'){ 5 return true; 6 } 7 return false; 8 } 9 public boolean isOp(char c){ 10 for(int i=0;i<op.length;i++){ 11 if(op[i]==c){ 12 return true; 13 } 14 } 15 return false; 16 } 17 public boolean isOp(String s){ 18 for(int i=0;i<strOp.length;i++){ 19 if(strOp[i].equals(s)){ 20 return true; 21 } 22 } 23 return false; 24 }
(3) because you need to convert all the questions to String type for processing, you need to process the calculation formula.
1 public List<String> work(String str){ 2 List<String> list = new ArrayList<String>(); 3 char c; 4 5 //StringBuilder And StringBuffer It's essentially the same,Mainly StringBuilder Remove the cost of thread safety protection 6 //append()Method for character splicing 7 StringBuilder sb = new StringBuilder(); 8 for(int i=0;i<str.length();i++){ 9 c = str.charAt(i); 10 if(isDigit(c)){ 11 sb.append(c); 12 } 13 if(isOp(c)){ 14 if(sb.toString().length()>0){ 15 list.add(sb.toString()); 16 sb.delete(0, sb.toString().length()); 17 } 18 //c+""In order to meet list<String>Storage parameters for String type 19 list.add(c+""); 20 } 21 } 22 //Will last sb Data in to List Medium and empty sb 23 if(sb.toString().length()>0){ 24 list.add(sb.toString()); 25 sb.delete(0, sb.toString().length()); 26 } 27 return list; 28 } 29 public void printList(List<String> list){ 30 for(String o:list){ 31 System.out.print(o+" "); 32 } 33 }
(4) convert infix expression to suffix expression, and then use stack to calculate
public List<String> InfixToPostfix(List<String> list){ List<String> Postfixlist = new ArrayList<String>();//Store suffix expression Stack<String> stack = new Stack<String>();//Staging operator for(int i=0;i<list.size();i++){ //Stack by priority String s = list.get(i); if(s.equals("(")){ stack.push(s); }else if(s.equals("*")||s.equals("/")){ stack.push(s); }else if(s.equals("+")||s.equals("-")){ if(!stack.empty()){ while(!(stack.peek().equals("("))){ Postfixlist.add(stack.pop()); if(stack.empty()){ break; } } stack.push(s); }else{ stack.push(s); } }else if(s.equals(")")){ while(!(stack.peek().equals("("))){ Postfixlist.add(stack.pop()); } stack.pop(); }else{ Postfixlist.add(s); } if(i==list.size()-1){ while(!stack.empty()){ Postfixlist.add(stack.pop()); } } } return Postfixlist; } /** * Suffix expression evaluation */ public int doCal(List<String> list){ Stack<Integer> stack = new Stack<Integer>(); for(int i=0;i<list.size();i++){ String s = list.get(i); int t=0; if(!isOp(s)){ t = Integer.parseInt(s); stack.push(t); }else{ if(s.equals("+")){ int a1 = stack.pop(); int a2 = stack.pop(); int v = a2+a1; stack.push(v); }else if(s.equals("-")){ int a1 = stack.pop(); int a2 = stack.pop(); int v = a2-a1; stack.push(v); }else if(s.equals("*")){ int a1 = stack.pop(); int a2 = stack.pop(); int v = a2*a1; stack.push(v); }else if(s.equals("/")){ int a1 = stack.pop(); int a2 = stack.pop(); int v = a2/a1; stack.push(v); } } } return stack.pop(); }
(V) methods for reading the contents of documents
1 public String[] getFile(String pathName) throws Exception { 2 // [1]Create one first File Body object of 3 File file = new File(pathName); 4 5 if (!file.exists()) 6 throw new RuntimeException("cannot find file!"); 7 // [2]Load BUfferedReader flow 8 BufferedReader br = new BufferedReader(new FileReader(file)); 9 String str; 10 String []arr = null; 11 // [3]Read line by line 12 while ((str = br.readLine()) != null) { 13 14 15 // The segmentation of data in files'，'Call the following split()function 16 arr = str.split(","); 17 18 } 19 return arr; 20 }
(VI) method of storing records in documents
// Store data in a file public void toFile(String path,int sumOfQ,String []wqs,int []Wresult,String TL,int []result,int[]arr) throws Exception { File file = null; FileWriter fWriter = null; file = new File(path); try { if (!file.exists()) { System.out.println("The file to read in data does not exist"); } fWriter = new FileWriter(file); fWriter.write("Number of questions:"+sumOfQ+"\n"); fWriter.write("Corresponding topics:\n"); for (int i = 0; i < sumOfQ; i++) { fWriter.write(wqs[arr[i]]+"\n"); } fWriter.write("Your submission at that time: "); for (int i = 0; i < Wresult.length; i++) { fWriter.write(Wresult[i]+" "); } fWriter.write("\n"); fWriter.write("Positive answer rate of this question: "+TL+"\n"); fWriter.write("Standard answer to this question: "); for (int i = 0; i < result.length; i++) { fWriter.write(result[i]+" "); } fWriter.write("\n"); fWriter.flush(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } finally { if (fWriter != null) { fWriter.close(); } } }
(VII) compare the standard answer with the user's input answer, and calculate the positive answer rate
1 // Method used to compare user's answer with standard answer 2 //Parameter is the answer array entered by the user 3 public String compare(int[] a,int[] results,int sumOfQ) { 4 double t = 0; 5 //Save the serial number of the wrong question to list Easy to call 6 List<Integer> falseQ = new ArrayList<Integer>(); 7 for (int i = 0; i < results.length; i++) { 8 if (a[i] == results[i]) 9 t++; 10 else { 11 12 falseQ.add(Integer.valueOf(i + 1)); 13 } 14 } 15 16 if (falseQ.isEmpty()) { 17 System.out.println("Congratulations, you have answered all the questions correctly!"); 18 } else { 19 System.out.print("The answer is completed, and the serial number of the existing problems is:"); 20 for (int i = 0; i < falseQ.size(); i++) { 21 System.out.print(falseQ.get(i) + " "); 22 } 23 } 24 System.out.println(); 25 System.out.println("Your positive response rate is:" + (DF_00(Double.valueOf(t / sumOfQ * 100))) + "%"); 26 27 return String.valueOf(DF_00(Double.valueOf(t / sumOfQ * 100)))+"%"; 28 }
(8) methods for standardizing various data and calculation results
1 public static double DF_00(Double b) { 2 //call DecimalForamt The instance object of class specifies the number of bits of data. 3 //Because I have to operate the data after the specification is completed, and I will force it to be converted. 4 DecimalFormat dFormat = new DecimalFormat("#.00"); 5 return Double.parseDouble(dFormat.format(b)); 6 }
(IX) methods for random questions
1 public int[] suiji(int sumOfQ,String[]wqs) { 2 3 int[] arr = new int[sumOfQ]; 4 arr[0] = (int) (Math.floor(Math.random() * (wqs.length))); 5 boolean isSame = true; 6 int j=0; 7 while (isSame == true) { 8 9 int suiji = (int) (Math.floor(Math.random() * (wqs.length))); 10 for (int i = 0; i < arr.length; i++) { 11 if (arr[i] == suiji) { 12 isSame = true; 13 break; 14 } else { 15 isSame = false; 16 continue; 17 } 18 19 } 20 if (!isSame) { 21 22 arr[j] = suiji; 23 j++; 24 isSame = true; 25 } 26 27 if (j == 3) { 28 break; 29 } 30 } 31 return arr; 32 }
(x) methods for users to input and save answers
//It is used to let the user enter the answer and save the answer entered by the user. public int [] Wresult(int sumOfQ) { System.out.println("Please enter your answers in turn:"); Scanner sc = new Scanner(System.in); String nextLine = sc.nextLine(); String[] temp = nextLine.split(" "); int[] Wresult = new int[sumOfQ]; for (int i = 0; i < temp.length; i++) { int wResult = Integer.parseInt(temp[i]); Wresult[i] = wResult; } return Wresult; }
(XI) test
1 public static void main(String[] args) { 2 // TODO Auto-generated method stub 3 4 LV lt = new LV(); 5 6 // Get topic content 7 try { 8 wqs = lt.getFile("Data structure phase II.txt"); 9 } catch (Exception e) { 10 // TODO Auto-generated catch block 11 e.printStackTrace(); 12 } 13 14 System.out.println("Please enter the number of questions:"); 15 Scanner scanner = new Scanner(System.in); 16 int sumOfQ = scanner.nextInt(); 17 18 arrs = lt.suiji(sumOfQ, wqs); 19 20 21 22 results = new int[sumOfQ]; 23 for (int i = 0; i < sumOfQ; i++) { 24 String str = wqs[arrs[i]]; 25 System.out.println((i + 1) + ": " + str); 26 List<String> list = lt.work(str); 27 List<String> list2 = lt.InfixToPostfix(list); 28 results[i] = lt.doCal(list2); 29 } 30 31 32 33 int[] Wresult = lt.Wresult(sumOfQ); 34 35 36 String TL = lt.compare(results, Wresult, sumOfQ); 37 38 39 System.out.println("The correct answer is:"); 40 for (int i = 0; i < results.length; i++) { 41 System.out.println((i + 1) + ": " + results[i]); 42 } 43 44 45 System.out.println("This answer record is being stored for you. Please wait..."); 46 Thread thread = new Thread(); 47 48 try { 49 lt.toFile("inputFile.txt", sumOfQ, wqs, Wresult, TL, results,arrs); 50 } catch (Exception e1) { 51 // TODO Auto-generated catch block 52 e1.printStackTrace(); 53 } 54 55 try { 56 Thread.sleep(1000); 57 thread.start(); 58 System.out.println("Records stored in inputFile.txt!"); 59 } catch (InterruptedException e) { 60 // TODO Auto-generated catch block 61 e.printStackTrace(); 62 } 63 64 65 }