Question

我看到这种幻灯片,旨在说明建筑商。我现在混淆不清,因为它有两个建筑商,在第二个建筑中,他们的工作相同,接受将pa升至零。为什么编码员需要重复<代码>,即:id = id;这一名称=名称;? 为什么这一类别甚至需要两个建筑商?

class Student{
      private int id;
      private String name;
      private double gpa;
      public Student(int id, String name, double gpa){
        this.id = id;  this.name = name;   this.gpa = gpa;
      }
      public Student(int id, String name){
        this.id = id;  this.name = name;   gpa = 0.0;
      }
      public boolean equals(Student other){
          return id == other.id && name.equals(other.name) 
                       && gpa == other.gpa;
      }
      public String toString(){
        return name + " " + id + " " + gpa;
      }
      public void setName(String name){
        this.name = name;
      }
      public double getGpa(){
        return gpa;
      }
    }

Answer 1

As with most contrived examples, there is often no obvious reason other than to show that the overloading is possible. In this example, I would be tempted to refactor the second constructor like this:

 public Student(int id, String name){
    this( id, name, 0.0 );
  }

Answer 2

现有2个建筑商,因为它显示了建筑商超负荷的概念:

拥有1个以上的建筑商(名称和回归类型(建筑商的类别为违约回报类型),但具有不同的参数(不同的签名)

负荷过重的建筑或方法参数可在型号和参数号......以及甚至顺序上有所改动。

the instances of the class / objects that you create invokes constructors at time of creation.. so at that time you could provide 2 or 3 parameters depending upon which constructor you want to use.. if you provide 3 it uses 3 parameter constructor..and 2 parameters then it uses 2 parameter constructor

It is basically the need of sometimes providing gpa or sometimes not.. therefore having initialization of objects with different values..

Answer 3

The constructor is overloaded (same name and return type with different parameters i.e different signature) so that you can initiate an instance of the class in different ways. One with a GPA that you choose and another one with a default GPA 0.0

Answer 4

它有2个建筑师,这样你就可以创造像学生这样的学生。

Student s = new Student(1, "Bob");

或

Student s = new Student(1, "Bob", 4.0);

Answer 5

如前所述,这被称为建筑商超载。这类似于超载功能,因为你可以有两种功能,名称相同,但签名不同。

举例来说,不提供《政府采购协议》将其设定为0.0(假定以后会改变)。可能的情况是,某些未来方法取决于《政府采购协议》的价值,即:界定的<<>>,而这两家建筑商就是这样做的。

Answer 6

让我们承担学生升学的要求,像甘帕一样,在增加学生的同时,如果是这样,你会创造机会。

Student s = new Student(5,"stud1",4.0);

让我们承担某些班级的升学,在升学的同时,一定要打克帕,那么你的学生目标将是<代码>。学生=新学生(6,“stud2”);,其中含蓄地将学生格格帕作为ZERO。

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