[英]Java Scanner issues, Notecard class
我正在嘗試制作一個基本上是虛擬便簽紙的程序。 每個記錄卡都有一個字符串,用於表示問題和答案,以及現在多次被問到的計數。 我在許多情況下都使用掃描儀,但我認為使用不正確,並且不確定原因。 該程序將讓我回答前兩個問題,告訴我無論如何它們都是不正確的,並跳過讓我回答最后一個問題。 這是筆記卡類:
public class Notecard {
public String ans;
public String q;
public int count;
public Notecard(String q, String ans) {
this.q = q;
this.ans = ans;
this.count = 0;
}
public Boolean answer(String effort) {
if (this.q.toUpperCase().equals(effort.toUpperCase())) {
System.out.println("Correct!");
return true;
} else {
System.out.println("Incorrect! Correct answer:" + this.ans);
count++;
return false;
}
}
public void clearCount() {
this.count = 0;
}
public String getQ() {
return this.q;
}
}
這是我的另一個文件:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;
import java.util.Scanner;
public class CreateNotecard {
int trys;
public static void main(String[] args) {
System.out.println("Get ready to be quizzed \n\n");
ArrayList<Notecard> notecards = makeCards();
quiz(notecards);
}
static ArrayList<Notecard> makeCards() {
ArrayList<Notecard> notecards = new ArrayList<Notecard>();
try {
BufferedReader in = new BufferedReader(new FileReader(
"notecards.txt"));
String str;
str = in.readLine();
while ((str = in.readLine()) != null) {
String[] argg = str.split(",");
notecards.add(new Notecard(argg[0], argg[1]));
}
in.close();
} catch (IOException e) {
System.out.println("File Read Error");
}
return notecards;
}
static void quiz(ArrayList<Notecard> notecards) {
ArrayList<Notecard> backupList = notecards;
Scanner sc = new Scanner(System.in);
long seed = System.nanoTime();
Collections.shuffle(notecards, new Random(seed));
int total = notecards.size();
int correct = 0;
for (Notecard x : notecards) {
System.out.println(x.getQ());
String effort = sc.next();
Boolean nailedIt = x.answer(effort);
if (nailedIt) {
correct++;
}
}
System.out.println("Total Notecards: " + total + "\nTotal Correct: "
+ correct);
System.out.println("Accuracy: " + (correct / total));
System.out.println("Do you want to repeat? Put \"y\" or \"n\"");
String choice1 = sc.nextLine();
if (choice1.toUpperCase().equals("Y")) {
System.out.println("Use only cards missed or all? Type \"missed\" or \"all\"");
String choice2 = sc.nextLine();
if (choice2.toUpperCase().equals("MISSED")) {
quiz(notecards);
} else {
quiz(backupList);
}
} else {
return;
}
}
}
我有一個用於此程序的文本文件,其中包含
19-9,10
square root of 4,2
capitol of Missouri,Jefferson City
Blastoise's 1st evolution,squirtle
我的輸出是
Get ready to be quizzed
square root of 4
2
Incorrect! Correct answer:2
capitol of Missouri
Jefferson City
Incorrect! Correct answer:Jefferson City
Blastoise's 1st evolution
Incorrect! Correct answer:squirtle
Total Notecards: 3
Total Correct: 0
Accuracy: 0
Do you want to repeat? Put "y" or "n"
您正在比較錯誤的事情:
public Boolean answer(String effort) {
if (this.q.toUpperCase().equals(effort.toUpperCase())) {
應該
if (this.ans.toUpperCase().equals(effort.toUpperCase())) {
問題在於Scanner
類正在尋找定界符來創建令牌,默認情況下是空白 。 由於您輸入“ 2”,所以Scanner.next()
找不到分隔符,因此也沒有標記。
例如,如果輸入“ Jefferson City”,則Scanner
找到一個定界符,因此找到兩個標記。 在這種情況下, sc.next
僅是“ Jefferson”(沒有“ City”,這是下一個標記)。
解? 從stdin讀取行並使用sc.nextLine()
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