java - 为什么我的 java 程序不接受用户的字母输入？

Question

编辑:我的问题已部分解决。现在我可以输入文本了，但是在我输入“shiphalf”值后什么也看不到。我是否错误地构建了 if else 语句？

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我试图让人们输入优惠券代码，但我无法弄清楚如何让控制台知道用户正在输入文本。我觉得错误就在这里:

        System.out.println("Enter a Coupon Code: ");
        String ship = input.nextLine(); 

但我不完全确定。下面是完整的源代码:

package pseudoPackage;

import java.util.Scanner;

public class PseudoCode {

    public static void main(String[] args) {


        Scanner input = new Scanner(System.in);


        int ship1 = 0;
        int ship2 = 6;
        int ship3 = 2;
        String shiphalf = null;

        System.out.print("How much will shipping cost you?");
        System.out.println();
        System.out.print("Enter your textbook cost in dollars without the $: ");
        double cost = input.nextDouble();



        if ( cost >= 100 ) {
            System.out.println("Your shipping costs are $0");
        } else if ( cost < 100 && cost > 50 ) {
            System.out.println("Your shipping cost is $6");
        } else if ( cost < 50 ) {
            System.out.println("Your shipping cost is $2");
        }

        System.out.println("Enter a Coupon Code: ");
        String ship = input.nextLine(); 

        if ( ship == shiphalf && cost >= 100 ) {
            System.out.println("Your shipping costs are $0");
        } else if ( ship == shiphalf && cost < 100 && cost >50 ) {
            System.out.println("Your shipping costs are $3 ");
        } else if ( ship == shiphalf && cost < 50 ) {
            System.out.println("Your shipping costs are $1");
        }


    }

}

Answer 1

你的代码有两个问题:
1. 使用 input.next() 而不是 input.nextLine()。
2.将您的 if conditional 更改为 ship.equals("shiphalf")。请记住，您使用 .equals() 来比较 2 个字符串。

这是你的最终代码:

package pseudoPackage;
import java.util.Scanner;

public class PseudoCode {

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);

        int ship1 = 0;
        int ship2 = 6;
        int ship3 = 2;
        String shiphalf = null;

        System.out.print("How much will shipping cost you?");
        System.out.print("\nEnter your textbook cost in dollars without the $: ");
        double cost = input.nextDouble();

        if ( cost >= 100 ) {
            System.out.println("Your shipping costs are $0");
        } else if ( cost < 100 && cost > 50 ) {
            System.out.println("Your shipping cost is $6");
        } else if ( cost < 50 ) {
            System.out.println("Your shipping cost is $2");
        }

        System.out.println("Enter a Coupon Code: ");
        String ship = input.next(); 

        if ( ship.equals("shiphalf") && cost >= 100 ) {
            System.out.println("Your shipping costs are $0");
        } else if ( ship.equals("shiphalf") && cost < 100 && cost >50 ) {
            System.out.println("Your shipping costs are $3 ");
        } else if ( ship.equals("shiphalf") && cost < 50 ) {
            System.out.println("Your shipping costs are $1");
        }
    }
}