如何在泛型方法中修复“错误：二元运算符的错误操作数类型”？

Question

我正在尝试打印数组中特定范围的内容。而且，我需要使用泛型方法，但我不断收到这些错误，说二元运算符的操作数类型错误。我想问我哪部分做错了，我该如何解决错误？

我正在使用 drjava。

  Integer[ ] integerArray = { 1, 2, 3, 4, 5};
  Double[ ] doubleArray = { 1.1, 2.2, 3.3, 4.4, 5.5 };
  Character[ ] characterArray = { 'H', 'E', 'L', 'L', 'O' };
  Pet[ ] petArray = { new Pet( "Bob", "Tortoise", "TSA", "19950315" ),
                      new Pet( "SweetPea", "Horse", "Genie", "20030214" ),
                      new Pet( "Little", "Chicken", "John", "20190123" ),
                      new Pet( "Dale", "Chipmunk", "Sam", "20090527" ),
                      new Pet( "Smokey", "Bear", "USPW", "19440413" )     };
  
  System.out.printf( "%nRange of integerArray contains:%n" );
  printRange( integerArray, 1, 3); 
  
  System.out.printf( "%nRange of doubleArray contains:%n" );
  printRange( doubleArray, 1, 3 ); 

  System.out.printf( "%nRange of characterArray contains:%n" );
  printRange( characterArray, 1, 3 ); 
  
  System.out.printf( "%nRange of petArray contains:%n" );
  printRange( petArray, 1, 3 );
 
} // end main

// 这是我遇到错误的部分

public static <T> void printRange( T[ ] inputArray, T start, T stop ){

 // display array elements 
 // Error:bad operand type T for unary operator '++' and Error: bad operand types for binar operator
 
    for( T element = start; element < stop; element++ )    
    {
        //Error: bad operand types for binary operator '>='
        first type:  T
        second type: int
        // Error: bad operand types for binary operator '<='
        first type:  T
        second type: T
        //Error: bad operand types for binary operator '<'
        first type:  T
        second type: T
        if( start < stop && start >= 0 && stop <= inputArray[inputArray.length-1] )
        {
            System.out.printf( "%s", element.toString( ) );
        }
   
    } // end enhanced for loop

    System.out.println( );
 
} // end method printRange                                    
} // end class ArrayMethods

这是预期的输出。 integerArray 包含的范围：

2 3

2.2 3.3

E L

Answer 1

++、>.. 之类的操作只允许用于数字类型。对于start 和stop 变量，您应该使用int 类型。并且更容易复制源数组的特定范围来打印它：

public static <T> void printRange(T[] inputArray, int start, int stop) {
    T[] copy = Arrays.copyOfRange(inputArray, start, stop);
    System.out.println(Arrays.toString(copy));
}

更新：使用for循环：

for (int i = 0; i < inputArray.length; i++) {
    if (i >= start && i < stop) {
        System.out.printf("%s ", inputArray[i]);
    }
}