Preface:

The methods in C# are often used in C# programming, so what It's a method. How to use the method? I'll summarize it here and hope you can point out my shortcomings.

1 What is a method

Method is a mechanism in C# to reuse a bunch of code. A method is a piece of code. This code may have input values ​​and may return values. I remember that Teacher Mi once said a metaphor about methods (functions): a method is like a pot, and our rice and water are like parameters. Put the rice and water into the pot, and then you can cook. The method requires us to give it some parameters, and then it may give us some return values.
There are a large number of methods in the .net framework, such as the Show method in the MessageBox class, the WriteLine method and ReadLine method in the Console class, the Parse method of Int32, and the Next method of the Random class. Proficient use of the methods defined in the class library in .netframework will make writing programs faster and faster.

2 How to define methods
Methods are declared in a class or structure. When declaring, you need to specify the access level, return value, method name and any method parameters. Method parameters are placed in parentheses and separated by commas. Empty parentheses indicate that the method requires no parameters.
For example:
Example 1:

public static void SayHello()
{
     System.Console.WriteLine("Hello,World!");
}

Example 2:

  public static int Add(int x,int y)
        {
            int z=x+y;
            return z;
        }

and above Two common method definitions are defined. Example 1 takes no parameters, while Example 2 takes 2 parameters. If you want to pass parameters to the method, just provide them within parentheses when calling the method. For a called method, the variables passed in are called "parameters".
The parameters received by the method are also provided in a set of brackets, but the type and name of each parameter must be specified. The name does not have to be the same as the parameter.

3 Method Calling

When the method is called, you only need to pay attention to the parameters and the return of the method value question. For example, call the method SayHello() defined in Example 1. Just enter the code statement SayHello() directly inside another method;. For example, call the method Add() defined in Example 2. Directly enter the code statement inside another method

inta = 1, b = 2，c;
  c = Add(a,b);

4 The return value of the method

The method can return any type of value, It is also possible to return no value. The return value type is reflected in the header of the method.

For example: method definition format: public int Method1(int x,int y)

At this point you can see the return value of the Method1 method The type is int.

The return value of a method is often passed through the return statement. The return statement terminates the execution of the method in which it appears and returns control to the code that called the method. If the method is of void type, the return statement can be omitted. You can observe the following code:

publicstatic string GetStr()
        {          
            string str=string.Empty;
            return str;
            str =System.Console.Read().ToString();
      }

5. Method overloading

Method overloading is a means for a class to process different types of data in a unified way. In C#, the syntax stipulates that two or more methods in the same class can use the same name. If this happens, the method is called an overloaded method. When an overloaded method is called, C# will automatically call a specific method to execute based on the parameters of the calling method.
What is method overloading? In high-level languages ​​such as object-oriented, we are allowed to define multiple methods in a class with the same method name and different number and order of parameters between methods. For situations where the number of parameters is different or the parameter list is different, we call it The parameter list is different. It should be noted that the return value of the method is not mentioned here. That is to say, the following conditions determine whether a method constitutes an overload:
◆ In the same class;
◆ The method name is the same;
◆ The parameter list is different.
In the overloading of the method, the explicit priority matching calling method is the method with the same number of given parameters
ref and out cannot be used as the basis for overloading. When you need to use it, you can only choose one, not both. Use both at the same time
If the parameter is modified by ref or out, the parameter must be a variable
The return value of the method does not constitute an overloading condition. The number of parameters of the
method can constitute a heavy load. When the number of parameters of the method is the same as the type of parameters, the type of parameter can also constitute a heavy load.
Use array types as method parameters: the keyword params can only appear once and is the last one that appears in the parameters.

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