我的程序在
之后立即停止System.out.println("Would you like to calculate simple interest or compound interest?");
userInputStr = myScanner.next();
并且没有我能找到的支架问题。我知道它与括号有关但我找不到它。有什么建议吗？
这是我的代码（稍后我将实现方法）
import java.util.Scanner;
public class Interest
{
static double userInputDou;
static String userInputStr;
static double rate;
static double time;
static double principal;
static double interest;
static double subinterest;
static double cNum;
static double total;
static Scanner myScanner = new Scanner(System.in);
public static void main(String[] args)
{
System.out.println("Would you like to calculate simple interest or compound interest?");
userInputStr = myScanner.next();
if (userInputStr.equalsIgnoreCase("simple interest"))
{
System.out.println("Please enter the rate: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
rate = userInputDou;
}
else
{
System.out.println("Please enter a integer for the rate.");
}
System.out.println("Please enter the time: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
time = userInputDou;
}
else
{
System.out.println("Please enter an integer for the time.");
}
System.out.println("Please enter the principal: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
principal = userInputDou;
}
else
{
System.out.println("Please enter an integer for the principal.");
}
interest = (principal * rate * time);
System.out.println("Your interest is $" + interest);
System.out.println("Your total payment is $" + (interest + principal));
}
else if (userInputStr.equalsIgnoreCase("compound interest"))
{
System.out.println("Please enter the rate: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
rate = userInputDou;
}
else
{
System.out.println("Please enter a integer for the rate.");
}
System.out.println("Please enter the time: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
time = userInputDou;
}
else
{
System.out.println("Please enter an integer for the time.");
}
System.out.println("Please enter the principal: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
principal = userInputDou;
}
else
{
System.out.println("Please enter an integer for the principal.");
}
System.out.println("Would you like to compound the interest quarterly or annually?");
userInputStr = myScanner.next();
if (userInputStr.equalsIgnoreCase("quarterly"))
{
System.out.println("For how many quarters would you like to compound the interest for?");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
cNum = (userInputDou * 4);
subinterest = (principal * (1 + (rate / cNum)));
interest = Math.pow(subinterest, time);
total = (principal + interest);
System.out.println("Your quarterly compounded interest is $" + interest);
System.out.println("Your total payment is $" + total);
}
else
{
System.out.println("Please enter an integer for the number of quarters.");
}
}
else if (userInputStr.equalsIgnoreCase("annually"))
{
System.out.println("For how many years would you like to compound the interest for?");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
cNum = userInputDou;
subinterest = (principal * (1 + (rate / cNum)));
interest = Math.pow(subinterest, time);
total = (principal + interest);
System.out.println("Your annually compounded interest is $" + interest);
System.out.println("Your total payment is $" + total);
}
else
{
System.out.println("Please enter an integer fro the number of years.");
}
}
else
{
System.out.println("Please enter either 'quarterly' or 'annually'.");
}
}
}
}
答案 0 :(得分：1)
userInputStr = myScanner.next()等待来自控制台的输入。你需要输入内容。阻塞是很正常的。
根据您输入的评论＆＃34;简单＆＃34;然后输入了。我可以说这个字符串＆＃34;简单＆＃34;你没有做过任何顶级比较＆＃34; userInputStr.equalsIgnoreCase（＆＃34;简单兴趣＆＃34;）＆＃34;和＆＃34;否则if（userInputStr.equalsIgnoreCase（＆＃34;复利＆＃34;））＆＃34;
，程序终止。你需要键入＆＃34;简单兴趣＆＃34;或者＆＃34;复利＆＃34;看到任何进一步的活动。
答案 1 :(得分：1)
myScanner.next()只会获得一个令牌，这意味着它会获得该行中的第一个单词，但不会获得多个单词，并且您要检查多个单词：< / p>
if(userInputStr.equalsIgnoreCase("simple interest"))
例如，如果你运行它：
System.out.println("Would you like to calculate simple interest or compound interest?");
userInputStr = myScanner.next();
System.out.println(userInputStr); // !!
如果用户输入＆＃34;简单兴趣＆＃34;你会看到userInputStr只包含一个单词，＃34;简单＆＃34;。因此，您的整个应用程序将退出，因为最基本的应用程序是这样的：
public static void main(String[] args) {
System.out.println("Would you like to calculate simple interest or compound interest?");
userInputStr = myScanner.next();
System.out.println(userInputStr); // !!
if (userInputStr.equalsIgnoreCase("simple interest")) {
// .... do some stuff
} else if (userInputStr.equalsIgnoreCase("compound interest")) {
// .... do other stuff
}
}
因此，如果userInputStr可能与两个字的字符串匹配，那么应用程序将只是退出。
这种方法的一种方法是使用myScanner.nextLine()，因为这将获得整个用户输入行。
所以改变：
userInputStr = myScanner.next();
if(userInputStr.equalsIgnoreCase("simple interest"))
为：
userInputStr = myScanner.nextLine();
if(userInputStr.equalsIgnoreCase("simple interest"))
但请注意，这会增加另一个问题，因为当nextLine()或myScanner.next() myScanner.nextDouble()时，myScanner.nextInt()还会获得任何未被吞噬的行尾令牌。除了myScanner.nextXxx()之外，还有myScanner.nextLine()或大多数myScanner.nextDouble()。因此，每次拨打myScanner.nextLine()时，请立即拨打userInputDou = myScanner.nextDouble();
rate = userInputDou;
以吞下行尾令牌。
因此，例如，改变：
userInputDou = myScanner.nextDouble();
myScanner.nextLine(); // swallow the end-of-line token
rate = userInputDou;
成：
import java.util.Scanner;
public class TestScanner {
public static void main(String[] args) {
Scanner myScanner = new Scanner(System.in);
System.out.print("Please enter a multi-word sentence: ");
String input = myScanner.next();
System.out.println("Output: " + input);
myScanner.close();
}
}
为了亚历山大的利益，请运行此代码并输入＆＃34; Hello World＆＃34;
$('body').on('click', '.dashboard_leftNav_category a', function() {
var link = $(this).attr('showSection'); //changed from let link
var show = $('[section="'+link+'"]');
$('[section]').hide();
$('body').find(show).fadeIn();
$('html,body').scrollTop(0);
});
答案 2 :(得分：0)
您应该使用nextLine()而不是next()的扫描仪。
import java.util.Scanner;
公共课堂考试{
static double userInputDou;
static String userInputStr;
static double rate;
static double time;
static double principal;
static double interest;
static double subinterest;
static double cNum;
static double total;
static Scanner myScanner = new Scanner(System.in);
public static void main(String[] args)
{
System.out.println("Would you like to calculate simple interest or compound interest?");
userInputStr = myScanner.nextLine();
if (userInputStr.equalsIgnoreCase("simple interest"))
{
System.out.println("Please enter the rate: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
rate = userInputDou;
}
else
{
System.out.println("Please enter a integer for the rate.");
}
System.out.println("Please enter the time: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
time = userInputDou;
}
else
{
System.out.println("Please enter an integer for the time.");
}
System.out.println("Please enter the principal: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
principal = userInputDou;
}
else
{
System.out.println("Please enter an integer for the principal.");
}
interest = (principal * rate * time);
System.out.println("Your interest is $" + interest);
System.out.println("Your total payment is $" + (interest + principal));
}
else if (userInputStr.equalsIgnoreCase("compound interest"))
{
System.out.println("Please enter the rate: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
rate = userInputDou;
}
else
{
System.out.println("Please enter a integer for the rate.");
}
System.out.println("Please enter the time: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
time = userInputDou;
}
else
{
System.out.println("Please enter an integer for the time.");
}
System.out.println("Please enter the principal: ");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
principal = userInputDou;
}
else
{
System.out.println("Please enter an integer for the principal.");
}
System.out.println("Would you like to compound the interest quarterly or annually?");
userInputStr = myScanner.next();
if (userInputStr.equalsIgnoreCase("quarterly"))
{
System.out.println("For how many quarters would you like to compound the interest for?");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
cNum = (userInputDou * 4);
subinterest = (principal * (1 + (rate / cNum)));
interest = Math.pow(subinterest, time);
total = (principal + interest);
System.out.println("Your quarterly compounded interest is $" + interest);
System.out.println("Your total payment is $" + total);
}
else
{
System.out.println("Please enter an integer for the number of quarters.");
}
}
else if (userInputStr.equalsIgnoreCase("annually"))
{
System.out.println("For how many years would you like to compound the interest for?");
if (myScanner.hasNextDouble())
{
userInputDou = myScanner.nextDouble();
cNum = userInputDou;
subinterest = (principal * (1 + (rate / cNum)));
interest = Math.pow(subinterest, time);
total = (principal + interest);
System.out.println("Your annually compounded interest is $" + interest);
System.out.println("Your total payment is $" + total);
}
else
{
System.out.println("Please enter an integer fro the number of years.");
}
}
else
{
System.out.println("Please enter either 'quarterly' or 'annually'.");
}
}
}
}