由于我的if语句导致的编译错误

Question

I clearly don't understand what I am doing here... I am pretty certain that my errors are only in the code I included, but I do have other classes also. If I could rename this to a better title, let me know, Or if I can include any more info let me know. From what I see on this website, I believe you guys will know exactly what the compilation errors mean, and know what I did wrong.

Here is my code:

import java.io.PrintStream;
public class Shape
{
   public static void init( String args[] )
   {
      Shape[] shapes = new Shape[ 4 ];
      shapes[ 0 ] = new Circle( 22, 88, 4 );
      shapes[ 1 ] = new Square( 71, 96, 10 );
      shapes[ 2 ] = new Sphere( 8, 89, 2 );
      shapes[ 3 ] = new Cube( 79, 61, 8 );

      for ( Shape currentShape : shape );
      {
         System.out.printf( "%s: %s", 
         currentShape.getName(), currentShape );

         Object localObject;

         if ( currentShape objectof TwoDimensionalShape )
         { 
             localObject = (TwoDimensionalShape)currentShape; 

            TwoDimensionalShape twoDimensionalShape = 
               ( TwoDimensionalShape ) currentShape;

            System.out.printf( "%s's area is %s\n", 
               currentShape.getName(), twoDimensionalShape.getArea() );
         } 

         if ( currentShape objectof ThreeDimensionalShape; )
         {
            ThreeDimensionalShape threeDimensionalShape = 
               ( ThreeDimensionalShape ) currentShape;

            System.out.printf( "%s's area is %s\n", 
               currentShape.getName(), threeDimensionalShape.getArea() );
            System.out.printf( "%s's volume is %s\n",
               currentShape.getName(), 
               threeDimensionalShape.getVolume() );
         } 

         System.out.println();
      } 
   } 
} 

My compilation errors:

ShapeTest.java:21: error: ')' expected
         if ( currentShape objectof TwoDimensionalShape )
                          ^
ShapeTest.java:21: error: ';' expected
         if ( currentShape objectof TwoDimensionalShape )
                                                       ^
ShapeTest.java:21: error: variable declaration not allowed here
         if ( currentShape objectof TwoDimensionalShape )
                                    ^
ShapeTest.java:33: error: ')' expected
         if (( currentShape objectof ThreeDimensionalShape; ))
                                    ^
ShapeTest.java:33: error: illegal start of expression
         if (( currentShape objectof ThreeDimensionalShape; ))
                                                          ^
ShapeTest.java:33: error: illegal start of expression
         if (( currentShape objectof ThreeDimensionalShape; ))
                                                             ^
6 errors

Answer 1

There's no objectof operator in Java, I think you meant instanceof . Also, there's a misplaced semicolon inside one of the conditions. Rewrite the conditions like this:

if (currentShape instanceof TwoDimensionalShape)
if (currentShape instanceof ThreeDimensionalShape)

Answer 2

Java has an instanceof operator instead of objectof

In Line 21 Replace if (currentShape objectof TwoDimensionalShape) with if(currentShape instanceof TwoDimensionalShape){ //more code }

In Line 33 if (currentShape objectof ThreeDimensionalShape;) with if(currentShape instanceof ThreeDimensionalShape){ //more code }