使用扫描仪从用户输入中读取整数

Question

In the program i am creating i am creating a menu for the user made by using integer variables, when the user selects one they will activate that option in the menu. I am trying to use readnextInt but it is not working and i am not sure why. The code for the scanner is not working.

import java.util.Scanner;


 public class username
      {
    public static void main(String[] args)
{


    {   
       int Floor;
       Floor = 0;

       int Destination;
       Destination = 0;

       int UseLift;
       int AuditReport;
       int ExitLift;
       int a;


       UseLift = 1;
       AuditReport = 2;
       ExitLift = 3;
       a = read.NextInt;


       Scanner b = new Scanner(System.in);
       int a = in.nextInt();

       if (a == 1)
      System.out.println(" Enter your name ");

       else if (a == 2)
    System.out.println("");

       else if(a == 3)
    System.out.println(" Please Exit Lift ");

{

Answer 1

This line has your error.

Scanner b = new Scanner(System.in);
int a = in.nextInt();

Your scanner is called b, not in. Use b.nextInt() instead.

Scanner b = new Scanner(System.in);
int a = b.nextInt();

Also you have an errant Read.nextInt(), and you haven't defined Read. I don't think that line is trying to do anything, so just delete it.

Answer 2

First, what is read ? I don't see it defined as a Scanner anywhere.

Second, once read is defined ( Scanner read = new Scanner(System.in); ), then you can call nextInt() , not NextInt . All methods need those parentheses when trying to call them.

Answer 3

Errors :

The statement

a = read.NextInt;

seems redundant. variable read is undefined.

a = read.NextInt;

Scanner b = new Scanner(System.in);
int a = in.nextInt();

Variable in is undefined but used to read nextInt() .

int a = in.nextInt();

It must be pointing to instance of Scanner class. Replace it with b .

You have defined a twice within the same scope. And hence your IDE must be showing a red line under

int a;
...
...
Scanner b = new Scanner(System.in);
int a = in.nextInt();

And, lastly, not an error but your code does not follow JAVA naming conventions for variable names and class names. For more details Read Java Naming Conventions

Corrections suggested :

1. Remove a = read.nextInt; as it seems redundant.
2. Remove int a; as you are redefining it after Scanner instantiation.
3. Change int a = in.nextInt(); to int a = b.nextInt();

Answer 4

Remaining code is correct just change this line "int a = in.nextInt();" to "int a = b.nextInt();" as b is the name of your scanner and nextInt() is method belongs to Scanner class "in.nextInt()" is incorrect.