Java's Scanner class

The use of reference data types is different from defining variables of basic data types. The variable definition and assignment of reference data types has a relatively fixed procedure or format.

1 datatype variable name =   new datatype();

Each reference data type has its function, and we can call the function of an instance of that type.

variablename.methodname();

Scanner class: It is a kind of reference data type. We can use this class to complete the user keyboard input and obtain the input data.

Steps to use Scanner :

1. Import package: import java.util.Scanner;
 2. Create object instance: Scanner sc = new Scanner(System.in);

Call method:

1  int   i = sc.nextInt(); used to receive the number entered from the console
 2 String s = sc.next(); used to receive the string entered from the console

ScannerDemo.java code file

1  /* 
2  Reference data type, introduce a class Scanner
 3  java already exists, it is a class made by Sun company for us, use him
 4  to define reference data type variables, which are different from basic type variables
 5    int a = 1;
 6      format :
 7        Type variable name = new type();
 8      Example: Create a variable of Scanner class
 9        Scanner sc = new Scanner();
 10        int a = 1;
 11      Each reference type has its own function, how to use the function
 12      Formula:
 13        Variable. Function name ()
 14        
15      Scanner class, role, let me accept keyboard input on the command line
 16      Use Scanner class steps:
 17        1. Import the package, specify the folder where the class is located, the keyword import
 18           java folder - util folder
19        2. Formula, create Scanner type variable
 20        3. Variable. Use the functions in Scanner class to complete keyboard input 
 21  */ 
22  import java.util.Scanner;
 23  public  class ScannerDemo{
 24      public  static  void main(String[] args){
 25          // Type variable name = new type();
 26          // Create Scanner, class variable 
27          Scanner sc = new Scanner(System.in);
 28          //Variable.Function name() accepts keyboard input
 29          / / Function: nextInt() accepts keyboard input, ensuring that the input is an integer
 30          // The data accepted by the function is an integer, and the result after the function runs is an integer type 
31          inti = sc.nextInt();
 32          System.out.println(i+5 );
 33          
34          // Another function of the Scanner class next() accepts a string input from the keyboard 
35          String s = sc.next();
 36          System.out.println(s+9 );
 37      }
 38 }

operation result:

Java's Scanner class

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