Character flow comprehensive exercise problem solving process

stem ：

（ Practice questions ） Use the input stream to read the test question file , Each time a question in the question file is displayed . Read the character “*” Pause reading when , Waiting for the user to enter an answer from the keyboard . After the user has finished all the questions . The program gives the user a score (10 Divide a question ).
1）     The test questions are as follows ：

(1) Hero alliance S9 When did the global finals open ？
    A.2018-08-08  B. 2018-08-01 
    C.2019-10-01 D. 2019-10-02
********************
(2) Which of the following heroes does not belong to 《 Hero alliance 》？
   A. carter  B. Blind monk C. Jianhao  D. Hou Yi
********************
(3). Which of the following is not the line of gust swordsman Yasso ?
    A. The wind of death , Always my body .B. Face the wind !C. A true master , Always with an apprentice heart .D. Hassel gave ！
********************
(4). Hero League World S Sai Bei OMG base 50 The blood turning team is ?
    A.SKT B.Najin C.FNC D.G2
********************
（5） In the League of Heroes , The most successful hero is ?
    A Swift scout  B Steam robot  C The power of demacia  D The strong wind sword
********************

-------》 The program runs as follows ：
(1) Hero alliance S9 When did the global finals open ？
A.2018-08-08  B. 2018-08-01 
C.2019-10-01 D. 2019-10-02
Enter the selected answer （A、B、C、D）：D
(2) Which of the following heroes does not belong to 《 Hero alliance 》？
   A. carter  B. Blind monk C. Jianhao  D. Hou Yi
Enter the selected answer （A、B、C、D）：D
...
...

Complete the test questions , congratulations Your final score is ：20 branch .

*/

Print it first , Console printing succeeded

Add judgment statement , Make it appear * Pause reading when , Enter the answer , Give it a trial run

Basically achieve the effect we want , But when I output answers in lowercase letters , No matching value found , So even if my answer is correct, I won't score , So you can write an output error statement .

java in “==” Use review of ：

Because in Java in , If basic data type , be == Compare values ; If it's an object type , be == It compares the address of the object .

   // Basic data type    == The judgment is the value 
  String str1 = "hello";
  String str2 = "hello";
  System.out.println(str1 == str2);

Basic data type ,== The judgment is the value , The result is true.

// Reference data type ,== The judge is the address they store in memory 
        String str1 = new String("hi");
		String str2 = new String("hi");
		System.out.println(str1 == str2);

Reference data type ,== The judge is the address they store in memory , The result is false.

The previous statement

/         use String To store 
        String line;
        while ((line = br.readLine()) != null) {
            br.lines();
            if (!line.startsWith("*")) {
                System.out.println(line);
            } else {
                System.out.println(" Enter the selected answer （A、B、C、D）：");
                String choice = sc.next();
//                 Splice input answers 
                result = sb.append(choice.charAt(0)).toString();
            }
        }

//         Store total score 
        int sum = 0;
        for (int i = 0; i < result.length(); i++) {
//             Compare input results with answers 
            if (result.charAt(i) == anser.charAt(i)) {
                sum += 10;
            }
        }
        System.out.println(" Complete the test questions , congratulations   Your final score is ：" + sum + " branch .");

After improvement ：

//         use String To store 
        String line;
        while ((line = br.readLine()) != null) {
            br.lines();
            if (!line.startsWith("*")) {
                System.out.println(line);
            } else {
//                 Join a dead circle , Ensure that the wrong input can continue to run 
                boolean flag = true;
                while (flag) {
                    System.out.println(" Enter the selected answer （A、B、C、D）：");
                    String choice = sc.next();
//                     Select the input content and compare it with the set answer , All satisfied with “ It's not equal to A/B/C/D” Conditions 
                    if (!choice.equals("A") && !choice.equals("B")  && !choice.equals("C")  && !choice.equals("D")) {
                        System.out.println(" The answer you entered is incorrect , Please try again ");
                    } else {
                        //                 Splice input answers 
                        result = sb.append(choice.charAt(0)).toString();
                        flag = false;  // End cycle 
                    }
                }
            }
        }

Complete operation is available ：

(1) Hero alliance S9 When did the global finals open ？
	A.2018-08-08  B. 2018-08-01 
	C.2019-10-01 D. 2019-10-02
 Enter the selected answer （A、B、C、D）：
a
 The answer you entered is incorrect , Please try again 
 Enter the selected answer （A、B、C、D）：
A
(2) Which of the following heroes does not belong to 《 Hero alliance 》？
   A. carter   B. Blind monk  C. Jianhao   D. Hou Yi 
 Enter the selected answer （A、B、C、D）：
D
(3). Which of the following is not the line of gust swordsman Yasso ?
	A. The wind of death , Always my body .B. Face the wind !C. A true master , Always with an apprentice heart .D. Hassel gave ！
 Enter the selected answer （A、B、C、D）：
C
(4). Hero League World S Sai Bei OMG base 50 The blood turning team is ?
	A.SKT B.Najin C.FNC D.G2
 Enter the selected answer （A、B、C、D）：
B
（5） In the League of Heroes , The most successful hero is ?
	A Swift scout   B Steam robot   C The power of demacia   D The strong wind sword 
 Enter the selected answer （A、B、C、D）：
D
 Complete the test questions , congratulations   Your final score is ：30 branch .

 Process ended , Exit code  0

The complete code is as follows ：

package com.B.IOStream_14.CharDemo03.Ask;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;

//（ Practice questions ） Use the input stream to read the test question file , Each time a question in the question file is displayed .
//  Read the character “*” Pause reading when , Waiting for the user to enter an answer from the keyboard . After the user has finished all the questions .
//  The program gives the user a score (10 Divide a question ).
public class A4 {
    public static void main(String[] args) throws IOException {
//         Create an input stream object 
        BufferedReader br = new BufferedReader(new FileReader("Temp\\ Q & A questions .txt"));
//        BufferedWriter bw = new BufferedWriter(new FileWriter("Temp\\itDemo\\array1.txt"));
//       StringBuilder Splice input answers 
        StringBuilder sb = new StringBuilder();
// Keyboard entry 
        Scanner sc = new Scanner(System.in);
//         Set the answer 
        String anser = "DDCCD";
// Initialization selection 
        String result = null;
// Read the test question file 
//        char[] chs = new char[1024];
//        int len;
//while ((len= br.read(chs)) != -1){
//    System.out.println(new String(chs,0,len));
//}

//         use String To store 
        String line;
        while ((line = br.readLine()) != null) {
            br.lines();
            if (!line.startsWith("*")) {
                System.out.println(line);
            } else {
//                 Join a dead circle , Ensure that the wrong input can continue to run 
                boolean flag = true;
                while (flag) {
                    System.out.println(" Enter the selected answer （A、B、C、D）：");
                    String choice = sc.next();
//                     Select the input content and compare it with the set answer , All satisfied with “ It's not equal to A/B/C/D” Conditions 
                    if (!choice.equals("A") && !choice.equals("B")  && !choice.equals("C")  && !choice.equals("D")) {
                        System.out.println(" The answer you entered is incorrect , Please try again ");
                    } else {
                        //                 Splice input answers 
                        result = sb.append(choice.charAt(0)).toString();
                        flag = false;  // End cycle 
                    }
                }
            }
        }

//         Store total score 
        int sum = 0;
        for (int i = 0; i < result.length(); i++) {
//             Compare input results with answers 
            if (result.charAt(i) == anser.charAt(i)) {
                sum += 10;
            }
        }
        System.out.println(" Complete the test questions , congratulations   Your final score is ：" + sum + " branch .");

// Release resources 
        br.close();

    }
}