我的目标是创建一个使用 getter 和 setter 方法来添加或减去 2 个数字的应用程序，我已经碰壁了

Question

我在编译时不断收到错误（./计算器Java32和36缺少返回语句）我很难看到我的代码在哪里被破坏，我是java的新手（不用说我确定）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

当你不打算返回任何东西时，你必须使用 void 作为返回类型，就像通常的 setter 方法一样：

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;
}