Question

我目前有以下代码写道：

import java.util.Scanner;

public class TicketPriceWithDiscount {

public static void main(String[] args) {

    TicketPriceWithDiscount obj = new TicketPriceWithDiscount();

}

  public TicketPriceWithDiscount(){

    double regPrice = 9.25;
    double otherPrice = 5.25; // ages under 12 or over 65
    double discount = 2.00;
    String person;
    int pInput;

    Scanner keyboard = new Scanner(System.in);

    System.out.println("What is your age?");

    pInput = keyboard.nextInt();

    System.out.println("Do you have a coupon? Yes or no will do.");

    person = keyboard.nextLine();

    if(person == "yes" && pInput <= 12 || pInput >= 65){
        otherPrice = otherPrice - discount;
        System.out.println("Your ticket price is: " + otherPrice);

    } 

    else if(person == "yes" && pInput >= 12 && pInput <= 65){
        regPrice = regPrice - discount;
        System.out.println("Your ticket price is: " + regPrice);
    } 

    else if(pInput <= 12 || pInput >= 65){
        System.out.println("Your ticket price is: " + otherPrice);
    } 

    else if(pInput >= 12 || pInput <= 65) {
        System.out.println("Your ticket price is: " + regPrice);
    }

}

}

该程序运行到我要求该人输入或不输入优惠券的程度。

System.out.println("Do you have a coupon? Yes or no will do.");

    person = keyboard.nextLine();

此时，程序不会等待输入并根据年龄输入完成if语句，它会等待用户的回复。

用于输入年龄的输出，对优惠券问题说是或否，以及程序根据这些答案继续运行。

我尝试过：

关闭扫描仪 - keyboard.close（）;
关闭第一个扫描程序后创建一个新的扫描程序。

非常感谢指导。

Answer 1

我认为您的nextLine会在您的

之后读取新的换行符

keyboard.nextInt();

尝试添加

keyboard.nextLine();

之后

keyboard.nextInt();

重置扫描仪。

Answer 2

您似乎遇到与this question with solution相同的问题。当然是奇怪的怪癖！

Answer 3

更改为：

import java.util.Scanner;

public class TicketPriceWithDiscount {

public static void main(String[] args) {

    TicketPriceWithDiscount obj = new TicketPriceWithDiscount();

}

  public TicketPriceWithDiscount(){

    double regPrice = 9.25;
    double otherPrice = 5.25; // ages under 12 or over 65
    double discount = 2.00;
    String person;
    int pInput;

    Scanner keyboard = new Scanner(System.in);

    System.out.println("What is your age?");
    pInput = keyboard.nextInt();

    System.out.println("Do you have a coupon? Yes or no will do.");
    //change to next() not nextLine()
    //because nextLine is used when you read a file
    person = keyboard.next();

     //use equals  not ==  and don't forget the parentheses
    if(person.equals("yes") && (pInput <= 12 || pInput >= 65)){
        otherPrice = otherPrice - discount;
        System.out.println("rani hna");
        System.out.println("Your ticket price is: " + otherPrice);

    } 

    //use equal not ==
    else if(person.equals("yes")  && pInput >= 12 && pInput <= 65){
        regPrice = regPrice - discount;
        System.out.println("Your ticket price is: " + regPrice);
    } 

    else if(pInput <= 12 || pInput >= 65){
        System.out.println("Your ticket price is: " + otherPrice);
    } 

    else if(pInput >= 12 || pInput <= 65) {
        System.out.println("Your ticket price is: " + regPrice);
    }

}

}

为什么这个程序不等待用户的输入？

3 个答案: