Foreword:
First we need to know why we need to use to construct function, or we need to know What problems can using the constructor solve for us:
1. When assigning the initial value, we may need to repeatedly write the object name, but if a constructor is used, it does not need to be so cumbersome. After all, the code is like that, the shorter the better (everyone knows it, I won’t say it out loud).
2. If there is such a attribute that users are not allowed to change at will, we generally define this attribute as a read-only attribute. Then this read-only type property cannot be assigned a value after instantiation. So how do we initialize it? As smart as you are, constructors can help us.
So has the compiler made such a useful thing for us? Of course, we have defined a class. If we do not write a constructor, then the compiler will automatically add a constructor without parameters to the class. And once we write a constructor, the compiler will not add this constructor without parameters for us.
Having said so much, what exactly is a constructor? The constructor is a special method used to create objects. The method name is the same as the class name. There is no return value, not even void. What is the syntax format?
[Access modifier]
{
//The body of the constructor
}
Let’s talk about several characteristics of the constructor:
1. Its name must be the same as the class name
For example:
public class Person { public Person(string name,char gender,int age) { this._name = name;//this指示代词 this._gender = gender; this._age = age; }
2. It cannot be called directly and must be called using the new operator.
In the chestnut above, when we call the Person class, we should write it like this:
Person zsPerson = new Person("Zhang San",'Male',18);
3. It canOverloading (A class can define constructors with different numbers of parameters or different types). One thing I didn't mention just now is that if we write a constructor, the original parameterless constructor will be gone. What should we do when we need it again? That is to write it again yourself.
The constructor can be used to create objects, and the object can be initialized in the constructor. The editor's debut time is still short, so I hope everyone can point out the shortcomings.
When I was watching of the C# video, I learned about the constructor and found it very interesting, because the understanding was not deep enough. Here is the first Make a brief summary.
First of all, we need to know why we need to use the constructor, or we need to know what problems using the constructor can solve for us:
1. When assigning the initial value, we may need to write the object name repeatedly, but if Using a constructor doesn't have to be so cumbersome. After all, the code is like that, the shorter the better (everyone knows it, I won’t say it out loud).
2. If there is such an attribute that users are not allowed to change at will, we generally define this attribute as a read-only attribute. Then this read-only property cannot be assigned a value after instantiation. So how do we initialize it? As smart as you are, constructors can help us.
So has the compiler made such a useful thing for us? Of course, we have defined a class. If we do not write a constructor, the compiler will automatically add a constructor without parameters to the class. Once we write a constructor, the compiler will not add this constructor without parameters for us.
Having said so much, what exactly is a constructor? The constructor is a special method used to create objects. The method name is the same as the class name. There is no return value, not even void. What is the syntax format?
[Access modifier]
{
//The body of the constructor
}
Let’s talk about several characteristics of the constructor:
1. Its name must be the same as the class name
For example:
public class Person { public Person(string name,char gender,int age) { this._name = name;//this指示代词 this._gender = gender; this._age = age; }
2. It cannot be called directly and must be called using the new operator.
In the above example, when we call the Person class, we should write it like this:
Person zsPerson = new Person("Zhang San",'Male',18);
3. It can be overloaded (A class can define constructors with different numbers of parameters or different types). One thing I didn't mention just now is that if we write a constructor, the original parameterless constructor will be gone. What should we do when we need it again? That is to write it again yourself.
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