Java 即使在导入包之后，display语句也会出错

我似乎不明白这段代码有什么问题。我不熟悉Java类。我在这里创建了一个新的Java类。我已经尝试了几乎所有的方法，但是我的构造函数下面的行上的错误现在真的很烦人。谁能帮帮我这里怎么了

另外，主类完全为空，粗体的行是编译器显示错误的行

import java.util.Scanner;
public class calculator extends FinalConsole {

        float x; 
        float y; 
        float v;
        float w;
        float z;
        char op;


        Scanner in= new Scanner(System. in); 
        public calculator(){
        System.out.println("You have selected calculator interface");
        }

        **System.out.println("Enter the number of digits: ");
        int values;
        values=in.nextInt();
        System.out.println("Select your funcion");
        op = in.next().charAt(0);**


        **if (values==2){**
        System.out.println("Enter first number: "); 
        x= in.nextFloat( );
        System.out.println("Enter second number: ");
        y=in.nextFloat();

            switch (op){

                case '+':
                 z=x+y;
                System.out.println("sum is:" +z);
                break;

                case '-':
                z = x-y;
                System.out.println("sum is:" +z);
                break;

                case '/':
                    z=y/x;
        System.out.println("sum is:" +z);

                break;
                case '*':
                z=x*y;
        System.out.println("sum is:" +z);
                break;
                default:
                System.out.println("Invalid operator");
        }
        }

         **if (values==3){**
        System.out.println("Enter first number: "); 
        x= in.nextFloat( );

        System.out.println("Enter second number: ");
        y=in.nextFloat();

        System.out.println("Enter third number: "); 
        v= in.nextFloat( );

        switch(op){
            case '+':
            z=w+x+y;
        System.out.println("sum is:" +z);
            break; 

            case '-':
            z=x-y;
        System.out.println("sum is:" +z);
            break;

            case '/':

             z=y/x;
        System.out.println("sum is:" +z);
            break;

            case '*':
            z=w*x*y;
        System.out.println("sum is:" +z);
            break;


            default:
            System.out.println("Invalid operator");
            break;

        }
         }

         **if (values==4){**

        System.out.println("Enter first number: "); 
        x= in.nextFloat( );

        System.out.println("Enter second number: ");
        y=in.nextFloat();

        System.out.println("Enter third number: "); 
        v= in.nextFloat( );

        System.out.println("Enter fourth number: "); 
        w= in.nextFloat( );

         switch (op){

             case '+':
            z=v+w+x+y;
        System.out.println("sum is:" +z); 
             break;

             case '-':
            z=x-y;
        System.out.println("sum is:" +z);
            break; 

             case '/':
            z=y/x;
            System.out.println("sum is:" +z);
            break;

             case '*':
            z=v*w*x*y;
        System.out.println("sum is:" +z);
            break;

             default:
            System.out.println("Invalid operator");
            break;
         }
     }
}

---

您应该将语句放在块或方法中，如下所示

import java.util.Scanner;
public class calculator  {
    float x;
    float y;
    float v;
    float w;
    float z;
    char op;
    Scanner in= new Scanner(System. in);
    public calculator(){
        System.out.println("You have selected calculator interface");
    }

    {
        System.out.println("Enter the number of digits: ");
        int values;
        values = in.nextInt();
        System.out.println("Select your funcion");
        op = in.next().charAt(0);
    }
}

---

它应该在像这个公共void calculator{System.out.println这样的方法中；}@PavneetSingh:这不是一个构造函数吗？是的，没有注意到类名，所以没有void，并将其余代码放在一个方法中为了最佳实践，遵循java约定，类名总是以大写字母开头