Question

只是想知道你是否可以帮助解决这个问题。代码和输出在下面提供。

do {
    System.out.println("would you kindly enter your age?");
    while (!sc.hasNext("[0-9]+")) {
        System.out.println("Please only use numbers.");
        sc.nextLine();
    }
    age = sc.nextByte();
    if (age >= 18) {
        System.out.println(""+age);}
    else if (age <= 17) {
        System.out.println("You must be 18 or older to rent a car if you input an incorrect age please try again otherwise close this page.");
    }
} while (age <= 17);

System.out.println("Would you kindly enter the first line of your address?");
address1 = sc.nextLine();

System.out.println("Would you kindly enter the second line of your address?");
address2 = sc.nextLine();

System.out.println("Would you kindly enter the third line of your address");
address3 = sc.nextLine();

sc.close();

输出：

请您输入您的姓名吗？   米
  你愿意进入你的年龄吗？   122个
  请问您输入地址的第一行吗？   请问您输入地址的第二行？
  1
  您能否进入地址的第三行？   1

Answer 1

这是因为Scanner.nextInt方法没有捕获输入的最后一个换行符（在数字之后，例如'5 \ n'），并且在调用Scanner.nextLine（）时，换行符被加载到String中。

Answer 2

在每个地址下将nextline更改为next next似乎解决了这个问题，不知道为什么会有效。

也感谢你帮助汤姆。

Answer 3

尝试这样的事情：

import java.util.Scanner;

class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    System.out.print("Continue? [Y/N]:");
    while (sc.hasNext() && (sc.nextLine().equalsIgnoreCase("y"))) {
      System.out.print("Would you kindly enter your age?");
      int age = sc.nextInt();
      sc.nextLine(); // To consume the left over newline;
      String address1, address2, address3;
      if (age >= 18) {
        System.out.println("Since you are " + age + " you are old enough to rent a car");
        System.out.println("Would you kindly enter the first line of your address?");
        address1 = sc.nextLine();
        System.out.println("Would you kindly enter the second line of your address?");
        address2 = sc.nextLine();
        System.out.println("Would you kindly enter the third line of your address");
        address3 = sc.nextLine();
      } else if (age <= 17) {
        System.out.println("You must be 18 or older to rent a car if you input an incorrect age please try again otherwise close this page.");
      }
      System.out.print("Continue? [Y/N]:");
    }
  }
}

在要求地址时，它会跳过地址的第一行

3 个答案: