Java中的不兼容类型错误 [英] Incompatible Types Error in Java

问题描述

我一直收到一个错误，指出存在不兼容的类型。我直接从一本书中复制了这本书，因为我们应该修改代码以增强战争的游戏。我有所有其他类完成和编译，但这一个是给我合适。下面是代码：

  public class ArrayStack< E>实现Stack< {
 
 private E [] data; 
 
 private int size; 
 
 public ArrayStack（）{
 data =（E []）（new Object [1]）; 
 size = 0; 
} 
 
 public boolean isEmpty（）{
 return size == 0; 
} 
 
 public Object pop（）{
 if（isEmpty（））{
 throw new EmptyStructureException（）; 
} 
 size--; 
 return data [size]; 
} 
 
 public Object peek（）{
 if（isEmpty（））{
 throw new EmptyStructureException（）; 
} 
 return data [size  -  1]; 
} 
 
 protected boolean isFull（）{
 return size == data.length; 
} 
 
 public void push（Object target）{
 if（isFull（））{
 stretch（）; 
} 
 data [size] = target; 
 size ++; 
} 
 
 protected void stretch（）{
 E [] newData =（E []）（new Object [data.length * 2]）; 
 for（int i = 0; i  newData [i] = data [i]; 
} 
 data = newData; 
} 
} 
  

错误发生在push数据[size] =目标;

EDIT :::
我现在收到此错误。
类型栈不接受参数
public class ArrayStack implements Stack

堆栈类如下。

  public interface Stack< E> {
 
 public boolean isEmpty（）; 
 
 public E peek（）; 
 
 public E pop（）; 
 
 public void push（E target）; 
 
} 
  

解决方案

code> push（）方法的参数类型将code>对象更改为 E

  public void push（E target）{
 if（isFull（））{
 stretch ; 
} 
 data [size] = target; 
 size ++; 
} 
  

同样，您也应该更改 pop（）和 peek（）到 E 。

  public E pop（）{
 if（isEmpty（））{
 throw new EmptyStructureException 
} 
 size--; 
 return data [size]; 
} 
 
 public E peek（）{
 if（isEmpty（））{
 throw new EmptyStructureException（）; 
} 
 return data [size  -  1]; 
} 
  

p>

I keep receiving an error that says that there are incompatible types. I copied this directly out of a book because we are supposed to make changes to the code to enhance the game of War. I have all of the other classes complete and compiled but this one is giving me fits. Here is the code:

public class ArrayStack<E> implements Stack<E> {

private E[] data;

private int size;

public ArrayStack() {
    data = (E[])(new Object[1]);
    size = 0;
}

public boolean isEmpty() {
    return size == 0;
}

public Object pop() {
    if (isEmpty()) {
        throw new EmptyStructureException();
    }
    size--;
    return data[size];
}

public Object peek() {
    if (isEmpty()) {
        throw new EmptyStructureException();
    }
    return data[size - 1];
}

protected boolean isFull() {
    return size == data.length;
}

public void push(Object target) {
    if (isFull()) {
        stretch();
    }
    data[size] = target;
    size++;
}

protected void stretch() {
    E[] newData = (E[])(new Object[data.length * 2]);
    for (int i = 0; i < data.length; i++) {
        newData[i] = data[i];
    }
    data = newData;
}   
}

The error is occurring in the push() method at the data[size] = target; line.

EDIT::: I'm now receiving this error. "type Stack does not take parameters public class ArrayStack implements Stack"

The stack class is as follows.

public interface Stack<E> {

public boolean isEmpty();

public E peek();

public E pop();

public void push(E target);

}

解决方案

Change Object to E as the push() method's parameter type.

public void push(E target) {
    if (isFull()) {
        stretch();
    }
    data[size] = target;
    size++;
}

Likewise, you should also change the declare return type of pop() and peek() to E.

public E pop() {
    if (isEmpty()) {
        throw new EmptyStructureException();
    }
    size--;
    return data[size];
}

public E peek() {
    if (isEmpty()) {
        throw new EmptyStructureException();
    }
    return data[size - 1];
}

Now your class is fully generic.

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