Java中的两个整数相加

Question

Im trying to sum two numbers from user input. But its not working

This is what I have done

import java.util.*;

public class EX2 {
  public static void main(String[] args) {
    int x;
    int y;

    Scanner x = new Scanner(System.in);
    x.nextInt();

    Scanner y = new Scanner(System.in);
    y.nextInt();

    int sum = x + y;

    System.out.println(x + " " + y);
    System.out.println(sum);
  }
}

the error code is

Error:(12, 17) java: variable x is already defined in method main(java.lang.String[])
Error:(13, 10) java: int cannot be dereferenced

Am I missing something here?

Answer 1

You reused the x and y variable names (hence the variable x is already defined in method main error), and forgot to assign the int s read from the Scanner to the x and y variables.

Besides, there's no need to create two Scanner objects.

public static void main(String[] args){
    int x;
    int y;

    Scanner sc = new Scanner(System.in);
    x = sc.nextInt();
    y = sc.nextInt();

    int sum = x + y;

    System.out.println(x +" "+ y);
    System.out.println(sum);
}

Answer 2

are you aware that the scanner and an integer are sharing the same name?

 int x;
 Scanner x = new Scanner(System.in);

that is invalid in java,think about using a more descriptive name for the scanner

Answer 3

import java.util.Scanner; 

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

/*
Step 1. Declare Variables 
*/

int varX;
int varY;
int sum;

/*
Step 2. Create a Scanner to take in user input
*/

Scanner scan = new Scanner(System.in);

/*
Step 3. varX and varY will take in the next two integers the user enters
*/

varX = scan.nextInt();
varY = scan.nextInt();

sum = varX + varY;

/*
Step 4. Print out the two chosen integers and display the sum
*/

System.out.println(varX + " + " + varY + " equals " + sum);
System.out.println(sum);
}

}