[英]Why isn't my java program working?? It doesn't allow me to input my string statement scale.
這是我編寫的將華氏溫度轉換為攝氏溫度,反之亦然的代碼。 老師說我們必須使用switch語句。
import java.util.Scanner;
public class hope
{
public static void main(String[]args)
{
Scanner keyboard = new Scanner(System.in);
System.out.println("Enter the number of degrees: ");
double degrees = keyboard.nextDouble();
System.out.println("Enter the scale: ");
String scale = keyboard.nextLine();
switch(scale)
{
case "F":
case "f":
double fahrenheit = (degrees - 32) * .5556;
System.out.println(degrees + scale + " equals " + fahrenheit + " degrees celcius");
break;
case "C":
case "c":
double celcius = (degrees + 32) * 1.8;
System.out.println(degrees + scale + " equals " + celcius + " degrees Fahrenheit");
break;
default:
System.out.println("I don't know what you're talking about. Chaw. ");
break;
}
}
}
問題是,當我運行它時,程序允許我輸入度數,然后顯示打印語句,然后跳轉到默認情況而不允許我輸入比例。
您需要使用新行。 Scanner.nextDouble()
僅將下一個標記讀取為double,而沒有行終止符。 閱讀double之后,可以添加keyboard.nextLine()
:
double degrees = keyboard.nextDouble();
keyboard.nextLine();
或在輸入行上使用Double.parseDouble(String)
:
String degreesString = keyboard.nextLine();
double degrees = Double.parseDouble(degreesString);
您輸入的兩倍之后的內容將由keyboard.nextLine();
占用keyboard.nextLine();
因此,您必須在keyboard.nextLine();
上keyboard.nextLine();
更多。
double degrees = keyboard.nextDouble();
keyboard.nextLine();
System.out.println("Enter the scale: ");
String scale = keyboard.nextLine();
如果“掃描儀”輸入實用程序不是強制性的,我建議您使用BufferedReader。
package com.tempcalculator;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
public static void main(String[] args) {
String degrees = getInput("Degrees?");
String scale = getInput("Scale?");
switch (scale.charAt(0)) {
case 'F':
case 'f':
double fahrenheit = (Double.parseDouble(degrees) - 32) * .5556;
System.out.println(degrees + scale + " equals " + fahrenheit + " degrees Celsius");
break;
case 'C':
case 'c':
double celsius = (Double.parseDouble(degrees) + 32) * 1.8;
System.out.println(degrees + scale + " equals " + celsius + " degrees Fahrenheit");
break;
default:
System.out.println("Whoops! Error 404: Requested scale was not found. ");
break;
}
}
public static String getInput(String prompt) {
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
System.out.print(prompt);
System.out.flush();
try {
return in.readLine();
} catch (IOException e) {
return "Error: " + e.getMessage();
}
}
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.