Question

感谢您提出的建议，这是我第一次使用stackoverflow，因为我对编程很新。我遇到的问题是我的程序在执行while循环后没有要求输入名称。具体来说，它似乎不会在循环后执行此行。 System.out.print（“输入节食者姓名：”）; String name = input.nextLine（）; 有人可以解释我可能错过使用扫描仪实用程序。

import java.util.*;

/**
 * CS-12J
 * Sweetner.java
 * Purpose:
 *
 * @version 1.0 3/18/13
 */

public class Sweetner {

   /**
    * The main method begins the execution of the program
    *
    *@param args not used
    */

    public static void main (String[] args) {
        Scanner input = new Scanner(System.in);
        String again = "yes";
        while (again.equals("yes")) {
            System.out.print("Enter the dieter's name: ");
            String name = input.nextLine();
            System.out.print("Enter the target weight of the dieter in pounds: ");
            double weightInPounds = input.nextDouble();

            //converts pounds to grams
            final double IBS_TO_GRAMS = 453.59;
            double weightInGrams = weightInPounds * IBS_TO_GRAMS;

            //finds lethal amout of sweetner for mouse
            final double MOUSE_WEIGHT = 30.0;
            final double LETHAL_DOSE = 100.0;
            final double MOUSE_LETHAL_PROPORTION =
                (double) LETHAL_DOSE / MOUSE_WEIGHT;

            //finds lethal amount of sweetner for human of given weight
            double lethalSweetner = MOUSE_LETHAL_PROPORTION * weightInGrams;

            //lethal number of cans
            final double SODA_SWEETNER = 0.001;
            final double SODA_GRAMS = 350;
            double lethalCans = lethalSweetner / (SODA_SWEETNER * SODA_GRAMS);

            //output
            System.out.println("For dieter: " + name);
            System.out.println("Dieter's target weight: " + weightInPounds
                + " pounds");
            System.out.println("Lethal dose in grams of sweetner is: "
                + lethalSweetner);
            System.out.println("Lethal number of cans of soda: "
                + lethalCans);

            //extra credit
            final int CANS_PER_DAY = 15;
            final double DAYS_IN_YEAR = 365.25;
            double yearsToLethal = lethalCans / (CANS_PER_DAY * DAYS_IN_YEAR);
            System.out.println("Years to lethal dose: " + yearsToLethal);
            System.out.print("Do you want to repeat the program? yes or no\n\t\t");
            again = input.next();
        }
    }
}

Answer 1

使用next（）而不是nextLine（）来获取名称：

String name = input.next(); // to get the name

nextLine（）扫描不可见的换行符，用户输入yes时就是这种情况。所以如果你想避免使用next（），只需输入input.nextLine（）;在循环结束时使用换行符。

Answer 2

在循环结束时尝试这个：

again = input.nextLine();

Answer 3

更改您的

String name = input.nextLine();

到此，它将起作用。

String name = input.next();

Answer 4

input.nextLine（）检索下一个换行符。在System.out.print（）中，您提供了“\ n”，它触发了nextLine（）方法。

System.out.print("Do you want to repeat the program? yes or no\n\t\t");
again = input.next();

在第二个语句之前需要另一个input.nextLine（），例如：

System.out.print("Do you want to repeat the program? yes or no\n\t\t");
input.nextLine();
again = input.next();

我希望这能解决你的问题。：）

Answer 5

如果节食者的姓名不能为空

System.out.print("Enter the dieter's name: ");
String name = scanLine.apply( input );

find scanLine here

而Loop取出第一线Java

5 个答案: