Question

sc.nextInt（）;给出了sc的错误。我只是想通过分配函数并调用它们来计算x和y的总和。这只是我必须完成的任务，但不幸的是我问了我的TA，但他不知道如何解决它。

import java.util.Scanner;
public class calculator {

int x;
int y;

public void setnumber (){
    System.out.println("Please Enter X");
    x = sc.nextInt ();
    System.out.println("Please Enter Y");
    y = sc.nextInt ();
}

public void sum (){
    int sum = x + y;
    System.out.println ("The Sum" + sum);
}

public static void main(String[] args) {

    Scanner sc = new Scanner (System.in);
    calculator sx = new calculator ();
    sx.setnumber ();
    sx.sum();
}
}

Answer 1

将扫描仪声明移动到setnumber方法：

import java.util.Scanner;
public class calculator {

int x;
int y;

public void setnumber (){
    Scanner sc = new Scanner (System.in);
    System.out.println("Please Enter X");
    x = sc.nextInt ();
    System.out.println("Please Enter Y");
    y = sc.nextInt ();
}

public void sum (){
    int sum = x + y;
    System.out.println ("The Sum" + sum);
}

public static void main(String[] args) {

    calculator sx = new calculator ();
    sx.setnumber ();
    sx.sum();
}
}

Answer 2

将Scanner sc从主方法中删除，在类级别定义它。

Answer 3

你应该了解范围。在主方法

之外看不到扫描仪对象

带有整数输入的扫描仪出错

3 个答案: