重载<< C++

Question

我试图重载<<运算符,以便我可以输出链表的内容.

所以,如果我有一个值为1,2,3的链表,我会调用:

cout << list << endl;

其中list的类型为LinkedList.我应该得到类似的东西:

1 2 3或1 | 2 | 3在终端.

我是否应该使用循环遍历列表并将每个节点的数据添加到出局？试图实现一个不需要查看节点类的方法......

ostream& operator <<(ostream& outs, const LinkedList& source)
{

    //use a loop to cycle through, adding each data to outs, seperated by a space or a |

    return outs;
}

像这样的结构能否正常运作？:

LinkedList::report(ostream& outs)    //thanks beta :)
{
    Node *currentPtr = headPtr;

    while(currentPtr != NULL)
    {
        outs << currentPtr->getData() << " ";   //thanks Rob :)

        currentPtr = currentPtr->getNextPtr();
    }

    return outs;
}

Answer 1

我建议这个:

ostream& operator <<(ostream& outs, const LinkedList& source)
{
    source.report(outs);
    return outs;
}

此方法看不到节点类.您将实现保留在LinkedList::report(ostream& outs)- 使用循环的位置.

编辑:
对您的report方法进行一些更正:

// It must have a return type (e.g. void), and it must be const because your
// operator takes a const argument, which must call this method
void LinkedList::report(ostream& outs) const 
{
    const Node *currentPtr = headPtr; // might as well make this const too

    while(currentPtr != NULL)
    {
        outs << currentPtr->getData() << " "; // you can use "|" if you want
        currentPtr = currentPtr->getNextPtr();
    }

    // no need to return anything
}