C # Concise Tutorial II

Tutorial section II: Reading command line input

Many programs can accept command-line input, and the following procedure is to accept the command line's loss
And then print it to the console screen.


Program 1-2:namedwelcome.cs

Namespace Declaration

Using System;


Program Start class

Class Namedwelcome {


Main begins program execution.

public static void Main (string[] args) {


Write to Console

Console.WriteLine ("Hello, {0}!", args[0]);

Console.WriteLine ("Welcome to the" C # station tutorial!);


}

}


Compile the program to NamedWelcome.exe and lose at the command line
into "Namedwelcome Joe". Be sure to add a name or something to the program.
Otherwise, the program will go wrong. Later we will discuss how to detect and avoid such errors.


In program 1-2, you can see that the argument list for the "Main" method has a parameter
Number, the name is "args", which is the parameter that the following program will use. "String[]"
The function is to define the parameter's data type as a string type and can hold one or more characters.
The square bracket "[]" means "string[]" is an array that can hold multiple parameters. Because
This, the parameter can be one or more arguments from the command line.


You will notice the Console.WriteLine ("Hello, {0}!", args[0]);
Line program. This line of procedures differs from the previous one, with an extra parameter ' {0} ' inside the quotation marks.
In a WriteLine statement, a parameter is a way to represent a method, and the format of the first argument
Is ' {0} ', the second is ' {1} ', and so on. Here "{0}" is represented by the end primer
The parameter "Args[0]" after the number to determine the contents of "{0}". According to this idea, we
Take a look at the argument "args[0]" after the closing quote content.

　　


The "args[0]" argument refers to the first element in the "args" array, and the second element
Is "args[1]", and so on. For example, I lose in command line mode
The value of "Namedwelcome Joe", "Args[0]" is "Joe."


Now let's look at the Code: Console.WriteLine ("Hello, {0}!",
Args[0]); , "{0}" will be replaced by the value in the parameter "args[0]" during execution,
Output to the screen along with the "Hello," front. So when we execute the program, we lose.
When you enter "Namedwelcome Joe", the following will be output:


>hello, joe!

>welcome to the C # station tutorial!