我是java的新手,所以请光临我。我有一个方法,应扫描大写或小写的3个字母之一,并返回该小写字母的小写版本。如果输入了不正确的字母,则会警告用户并重新填写一封信。我有两个问题,1:一旦方法运行,我得到输出的行,错误消息告诉用户无效输入而不等待输入! (所以第二个方法运行我在输入任何内容之前看到High, low or sevens (H/L/S):Invalid entry. Please try again using H/L/S!
然后再次调用该方法并且除了我的下一个问题之外所有工作都很好)2:从扫描仪获得的条目从未通过任何我的if语句,即使它应该。
我的代码:
private static char getHighLow(Scanner inScanner) {
System.out.print("High, low or sevens (H/L/S):");
String entered = inScanner.nextLine();
System.out.print(entered);
if(entered.equals("H") || entered.equals("h")){
return 'h';
}
else if (entered.equals("L") || entered.equals("l")){
return 'l';
}
else if(entered.equals("S") || entered.equals("s")){
return 's';
}
char result = 0;
while(result != 'l' || result != 'h' || result != 's'){
System.out.println("Invalid entry. Please try again using H/L/S!");
result=getHighLow(inScanner);
}
return result;
}
答案 0 :(得分:2)
您只需使用equalsIgnoreCase
并修剪输入的字符串即可。并添加一个while
循环,满足您的条件。
Scanner scanner = new Scanner(System.in);
boolean loop = true;
String choice = null;
while (loop) {
System.out.print("High, low or sevens (H/L/S):");
choice = scanner.nextLine();
if ("H".equalsIgnoreCase(choice.trim())
|| "L".equalsIgnoreCase(choice.trim())
|| "S".equalsIgnoreCase(choice.trim())) {
System.out.println("Correct Choice");
loop = false;
}
else
{
System.out.println("Wrong Choice");
}
}
System.out.print(choice);
答案 1 :(得分:2)
不使用while(),您可以像这样使用'else' -
private static char getHighLow(Scanner inScanner) {
System.out.print("High, low or sevens (H/L/S):");
String entered = inScanner.nextLine();
System.out.print(entered);
if(entered.equals("H") || entered.equals("h")){
return 'h';
}
else if (entered.equals("L") || entered.equals("l")){
return 'l';
}
else if(entered.equals("S") || entered.equals("s")){
return 's';
}
else {
System.out.println("Invalid entry. Please try again using H/L/S!");
return getHighLow(inScanner);
}
}
答案 2 :(得分:1)
char result;
while(true){
System.out.print("High, low or sevens (H/L/S):");
String entered = inScanner.nextLine();
System.out.print(entered);
if(entered.equals("H") || entered.equals("h")){
result = 'h';break;
}
else if (entered.equals("L") || entered.equals("l")){
result = 'l';break;
}
else if(entered.equals("S") || entered.equals("s")){
result = 's';break;
}else{
System.out.println("Invalid entry. Please try again using H/L/S!");
}
}
答案 3 :(得分:0)
嘿,你根本没有突破while循环。你看到了吗?
答案 4 :(得分:0)
这就是你想要的。这是迭代String中字符的程序。如果它们是H,L或S,则用小写字母转换它们。
package testproj;
import java.util.Scanner;
public class TestProj {
public static void main(String[] args) {
Scanner scanner = new Scanner("HLs");
String result = getHighLow(scanner);
System.out.println("Result :"+result);
}
private static String getHighLow(Scanner inScanner) {
System.out.println("High, low or sevens (H/L/S):");
String entered;
String result = "";
boolean isCharFound = false;
String temp = "";
while (inScanner.hasNext()) {
temp = inScanner.next();
System.out.println(temp);
for (int index = 0; index < temp.length(); index++) {
entered =new Character(temp.charAt(index)).toString() ;
if (entered.equals("H") || entered.equals("h")) {
result = result + 'h';
isCharFound = true;
} else if (entered.equals("L") || entered.equals("l")) {
result = result + 'l';
isCharFound = true;
} else if (entered.equals("S") || entered.equals("s")) {
result = result + 's';
isCharFound = true;
}
if (!isCharFound) {
System.out.println("Invalid entry. Please try again using H/L/S!");
}
isCharFound = false;
}
}
return result;
}
}