Question

我对Java非常陌生，我们将不胜感激！当我编译/运行＆＃34; Driver.java＆＃34;时，它会要求用户输入他们的名字。该计划应该采用的是该名称并将其传递给＃34; Greeter.java＆＃34;打印出最后的消息。

我试图实现一个接受字符串参数的构造函数，表示我的程序问候的人的姓名。我必须使用此参数来初始化我在＆＃34; Greeter＆＃34;中声明的私有实例变量。类。这就是我陷入困境的地方，但到目前为止我所拥有的是：

这是我的＆＃34; Driver.java＆＃34;：

import java.util.Scanner;

public class Driver
{
   public static void main(String[] args)
   {
      Scanner scanner = new Scanner(System.in);
      System.out.print("What is your name? ");
      String name = scanner.nextLine();
      Greeter greeter = new Greeter(name);
      String greeting = greeter.greet();
      System.out.println(greeting);
   }
}

这是我的Greeter.java：

public class Greeter
{
   String inputName; (This is where I got stuck)

   public string greet()
   {
      return "Hello " + inputName;
   }

}

Answer 1

您缺少构造函数

试

public class Greeter
{
   String inputName; 

   public Greeter (String inputName) {
     this.inputName = inputName;
   }

   public String greet()
   {
      return "Hello " + inputName;
   }
}

Answer 2

你需要创建一个构造函数来接受你在Main类中使用的参数：

public Greeter (String inputName) { // constructor with parameter that ll be called when Greeter's instance ll be created.
     this.inputName = inputName;
}

当任何地方Greeter greeter = new Greeter(字符串＆＃34;）; will be called then inputName`变量将被初始化。

所以每当你使用参数构造函数创建类的实例时，它都会初始化inputName变量。

public class Driver
{
   public static void main(String[] args)
   {
      Scanner scanner = new Scanner(System.in);
      System.out.print("What is your name? ");
      String name = scanner.nextLine();
      Greeter greeter = new Greeter(name);
      String greeting = greeter.greet();
      System.out.println(greeting);
   }
}

Answer 3

Greeter greeter = new Greeter(name);

要做到这一点，你需要一个构造函数，它接受String变量作为Greeter类

中的输入参数

public class Greeter {
 String inputName;

 public Greeter(String inputName) { // matching constructor
    this.inputName = inputName;
 }

 public String greet() {
    return "Hello " + inputName;
 }
}

Answer 4

通过以下代码

public class Greeter {

  private String name;

  public Greeter() { }

  public Greeter(String name) {
      this.name = name;
  }

  public String getName() {
      return name;
  }

  public void setName(String name) {
      this.name = name;
  }

  public String greet(){
      return "Hello "+ getName();
  }

}

public class Driver {

  public static void main(String[] args) {

      Scanner input = new Scanner(System.in);
      System.out.print("Enter your name : ");
      Greeter greeter = new Greeter(input.nextLine());
      System.out.println(greeter.greet());

  }

}

祝你好运!!!

Answer 5

改变你的Greeter课程。

public class Greeter{
   private String inputName;    

   public Greeter(){

   }

   public Greeter (String inputName) {
     this.inputName = inputName;
   }

   public String greet()
   {
      return "Hello " + inputName;
   }

}

如何在另一个类中使用一个类的字符串值？

5 个答案: