同时循环取出第一行Java

Question

谢谢您的建议，这是我第一次参加stackoverflow，因为我对编程还很陌生。我遇到的问题是执行while循环后，我的程序没有要求输入名称。具体来说，似乎在循环后不执行此行。System.out.print（“输入节食者的姓名：”）;字符串名称= input.nextLine（）;有人可以解释一下我可能无法使用Scanner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（）代替nextLine（）获得名称：

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

nextLine（）扫描不可见的换行符，当用户输入yes时似乎是这种情况。因此，如果要避免使用next（），只需输入input.nextLine（）;。在循环结束时使用换行符。

Answer 2

在循环末尾尝试：

again = input.nextLine();

Answer 3

更改您的

String name = input.nextLine();

为此，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();

您需要在第二条语句之前添加另一个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();

我希望这可以解决您的问题。 ：）

Answer 5

如果节食者的名字不能为空

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

find scanLine here