在类内部使用静态方法时没有输出（该类内部没有主函数）

huangapple
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英文:

No output while using static methods inside a class(the class which has no main function in it)

问题

以下是您提供的内容的翻译部分：

这是我的主类：

  1. public class App {
  2.     public static void main(String[] args) {
  3.         Student s1 = new Student();
  4.     }
  5. }

这是创建的类：

  1. class Student {
  2.     public static void f1() {
  3.         f2();
  4.     }
  5.     
  6.     public static String f2() {
  7.         return "hello";
  8.     }
  9.     
  10.     public Student() {
  11.         f1();
  12.     }
  13. }

现在，我在主类中创建了一个名为s1的对象，构造函数被调用，该构造函数包含f1()，所以f1()被调用，现在f1()调用了f2()，所以f2()被调用，因此我认为"hello"必须被打印出来，但实际上没有输出任何内容（什么都没有打印出来）。有人能解释一下可能的原因吗？

英文:

THIS IS MY MAIN CLASS:

  1. public class App {
  2. 	public static void main(String[] args){
  3. 		Student s1=new Student();
  4. 		
  5. 	};
  6. 	};

THIS IS THE CREATED CLASS:

  1. class Student {
  2. 	public static void f1(){
  3. 		f2();
  4. 	}
  5. 	public static String f2(){
  6. 		
  7. 		return "hello";
  8. 	}
  9. 	public Student(){
  10. 		f1();
  11. 	}
  13. }

Now , as i have created an object s1 in main class, the constructor is called ,which has f1() , so f1() is called , now f1() has f2(), so f2() is called , so i think "hello" must be printed but the output is not printed at all(nothing is printed). Can anyone please explain what the reason could be?

答案1

得分: 4

在打印和返回一个值之间有一个区别。
如果你希望它被打印出来，你应该尝试像这样做：

  1. class Student {
  2.     public static void f1(){
  3.         f2();
  4.     }
  5.     public static void f2(){
  6.         
  7.         System.out.print("hello");
  8.     }
  9.     public Student(){
  10.         f1();
  11.     }
  13. }
英文:

There is a difference between printing and returning a value.
If you want it to get printed, you should try doing something like this:

  1. class Student {
  2.     public static void f1(){
  3.         f2();
  4.     }
  5.     public static void f2(){
  6.         
  7.         System.out.print("hello");
  8.     }
  9.     public Student(){
  10.         f1();
  11.     }
  13. }

答案2

得分: 3

"f2()"正在返回"String"，但是"f1"没有将其打印出来：

  1. public static void f1(){
  2.     System.out.println(f2());
  3. }
  4. public static String f2(){    
  5.     return "hello";
  6. }
  7. public Student(){
  8.     f1();
  9. }
英文:

f2() is returning the String, but f1 is not printing it:

  1. public static void f1(){
  2.     System.out.println(f2());
  3. }
  4. public static String f2(){    
  5.     return "hello";
  6. }
  7. public Student(){
  8.     f1();
  9. }

答案3

得分: 3

要在控制台日志中打印，您应该尝试：System.out.println("Hello");

您正在返回该值，而不是打印它。

英文:

To be printed at the Console Log you should try: System.out.println("Hello");

You are returning the value not printing it.

答案4

得分: 2

你必须使用 System.out.println("Hello")，而不是 return "hello";

英文:

You have to use System.out.println("Hello") instead of return "hello";

答案5

得分: 2

I方法....

由于f2方法具有返回类型，为了获取从该方法获得的值，需要创建一个与返回类型兼容的引用，并使用相同引用代码编写单词"hello"，如下所示：

  1. class Student {
  2.     public static void f1() {
  3.         String x = f2(); // 调用方法
  4.         System.out.println(x);
  5.     }
  7.     public static String f2() {
  8.         return "hello";
  9.     }
  11.     public Student() {
  12.         f1();
  13.     }
  14. }

II方法......

你可以尝试这种方式：

  1. class Student {
  2.     public static void f1() {
  3.         System.out.println(f2()); // 调用方法
  4.     }
  6.     public static String f2() {
  7.         return "hello";
  8.     }
  10.     public Student() {
  11.         f1();
  12.     }
  13. }
英文:

I method....

Since the f2 method has a return type, in order to get the value obtained from it, make a reference of the type that is compatible with the return type and write the word hello using the same reference code as follows

  1. class Student {
  2. public static void f1(){
  3.     String x=f2(); //method calling
  4.     System.out.println(x);
  6. }
  7. public static String f2(){
  8.     
  9.     return "hello";
  10. }
  11. public Student(){
  12.     f1();
  13. }

}

II method......

You can try this way...

  1. class Student {
  2. public static void f1(){
  3.     
  4.     System.out.println(f2());//calling method
  6. }
  7. public static String f2(){
  8.     
  9.     return "hello";
  10. }
  11. public Student(){
  12.     f1();
  13. }}

huangapple
  • 本文由 发表于 2020年8月23日 16:49:29
  • 转载请务必保留本文链接：https://go.coder-hub.com/63545084.html
  • class
  • function
  • java
  • methods
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