我的目标是创建一个使用getter和setter方法添加或减去2个数字的应用程序，我碰到了砖墙

Question

我在编译时始终收到错误（./Calculator Java32＆36缺少return语句），我很难看到我的代码在哪里坏了，我是java的新手（不用说，我不确定）任何帮助将不胜感激。 谢谢。

    import javax.swing.JOptionPane;
    public class CalculatorTestDrive
    {
    public static void main(String[] args)
    {


   int user = Integer.parseInt(JOptionPane.showInputDialog(null, "If you would like to Add enter 1 or if you would like to Subtract enter 2"));
   while((user == 1)||(user == 2))
   {
   int a = Integer.parseInt(JOptionPane.showInputDialog(null, "Please Enter Your First Number"));
   int b = Integer.parseInt(JOptionPane.showInputDialog(null, "Please Enter Your Second Number"));
   Calculator one = new Calculator();

   one.setFirstnumber(a);
   one.setSecondnumber(b);
   }
   }
   }

public class Calculator
{

    private int x;
    private int y;
    private int z;
    int userImput1;
    int userImput2;
    int add = 1;
    int subtract = 2;
    int user;
    public void add()
    {
        z = x + y;
    }
    public void subtract()
    {
        z = x - y;
    }
    public int getFirstnumber()
    {
        return  x;
    }
    public int getSecondnumber()
    {
        return  y;
    }

    public int setFirstnumber(int userImput1)
    {
        x = userImput1;
    }
    public int setSecondnumber(int userImput2)
    {
        y = userImput2;
    }

}

Answer 1

当您不打算返回任何东西时，必须像往常那样使用setter方法，将void作为返回类型：

public void setFirstnumber(int userImput1)
{
    x = userImput1;
}
public void setSecondnumber(int userImput2)
{
    y = userImput2;
}

Answer 2

public void setFirstnumber(int userImput1)
{
    x = userImput1;
}
public void setSecondnumber(int userImput2)
{
    y = userImput2;
}