java - 为什么 if 语句后无法输入信息？没有错误显示

Question

如何让程序在 if 语句之后使用扫描器要求输入？

import java.util.Scanner;

public class App1 {

    public static void main(String[] Args) {

        Scanner keyboard = new Scanner(System.in);

        String gender;
        String fName;
        String lName;
        int age;
        String female = "F";
        String male = "M";
        String a = "";
        String gettingMarried = "y";
        String notGettingMarried = "n";

        System.out.println("What is your gender (M or F)");
        gender = keyboard.nextLine();
        System.out.println("What is your first name?");
        fName = keyboard.nextLine();
        System.out.println("What is your last name?");
        lName = keyboard.nextLine();
        System.out.println("Age:");
        age = keyboard.nextInt();
        System.out.println();

        if (gender.equals(female) && age >= 20) {
            System.out.println("Are you married " + fName + " (y or n?)");
            a = keyboard.nextLine();

        } else if (gender.equals(male) && age >= 20) {
            System.out.println("Are you married" + fName + "(y or n?)");
            a = keyboard.nextLine();
        }

    }
}

Answer 1

这是因为您使用的 nextInt() 只接受 int 值，而不是整行。当您再次尝试使用 keyboard.nextLine() 读取时，您捕获到的内容是您放置 int 的行的其余句子。

将 if 语句之前的 System.out.println(); 更改为 keyboard.nextLine();

编辑:如果您想要更详细的解释为什么必须在 keyboard.nextInt() 之后放置 keyboard.nextLine(); code>你可以引用我在另一个有同样问题的问题中的回答:Why isn't the scanner input working?

希望对你有帮助!