我試圖將鍵盤輸入轉(zhuǎn)換為整數(shù)，但我的程序不斷崩潰。當(dāng)輸入諸如“k”之類的字符時(shí)它起作用，但當(dāng)我輸入“5”時(shí)它會(huì)崩潰。關(guān)于我做錯(cuò)了什么的任何想法？// Getting an integer value.public static int getInt() { int numberEntered = 0; String entry = ""; Scanner keyboard = new Scanner(System.in); while (!keyboard.hasNextInt()) { entry = keyboard.next(); System.out.println("That is not an integer. " + "Please try again."); } numberEntered = Integer.parseInt(entry); System.out.print(numberEntered); return numberEntered;}輸出：Error given: k That is not an integer. Please try again. 8 Exception in thread "main" java.lang.NumberFormatException: For input string: "k" at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) at java.base/java.lang.Integer.parseInt(Integer.java:652) at java.base/java.lang.Integer.parseInt(Integer.java:770) at Program2.getInt(Program2.java:56) at Program2.problemSelectionMenu(Program2.java:40) at Program2.main(Program2.java:14)
2 回答
暮色呼如
TA貢獻(xiàn)1853條經(jīng)驗(yàn) 獲得超9個(gè)贊
您檢查以確保輸入具有下一個(gè) int，但是一旦Scanner具有下一個(gè) int，您就永遠(yuǎn)不會(huì)將 int 解析為entry，因此它仍然是錯(cuò)誤的輸入。您需要將int用戶輸入的分配給entry。您只需調(diào)用即可輕松完成此操作nextInt()：
while (!keyboard.hasNextInt()) {
entry = keyboard.next();
System.out.println("That is not an integer. " + "Please try again.");
}
numberEntered = keyboard.nextInt();
System.out.print(numberEntered);
return numberEntered;
烙印99
TA貢獻(xiàn)1829條經(jīng)驗(yàn) 獲得超13個(gè)贊
當(dāng)您將字符作為輸入提供時(shí)，while 循環(huán)條件為真，因此它進(jìn)入 while 循環(huán)并掃描字符和打印字符的值，但是當(dāng)您提供整數(shù)時(shí)，while 循環(huán)條件變?yōu)榧俨⑶也粫?huì)進(jìn)入 while 循環(huán). 在 while 循環(huán)之外，您正在解析整數(shù)，您不需要這樣做，因?yàn)槟鷮⒄麛?shù)作為輸入。您所要做的就是在 integer.parseInt(entry) 的位置，您必須掃描整數(shù)即 int i =keyboard.nextInt(); 因?yàn)樵?while 循環(huán)條件中，您只檢查您提供的輸入是否為整數(shù)。但是您沒有掃描整數(shù)的輸入。
試試這個(gè)?。?！
int numberEntered = 0;
String entry = "";
Scanner keyboard = new Scanner(System.in);
while (!keyboard.hasNextInt()) {
entry = keyboard.next();
System.out.println("That is not an integer. " +"Please try again.");
}
numberEntered = keyboard.nextInt();
System.out.print(numberEntered);
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