是否有用于C字符串的标准C ++迭代器? [英] Is there a standard C++ iterator for C strings?

问题描述

有时我需要使用通用的C ++迭代器范围接口[first, last)将C字符串传递给函数.在这些情况下，是否有标准的C ++迭代器类，或者不需要复制字符串或调用strlen()的标准方式?

我知道我可以将指针用作迭代器，但我必须知道字符串的结尾，什么使我需要调用strlen().

虽然我不知道这样的迭代器是否标准化，但我当然知道是可能的.回应讽刺的答案和评论，这是存根(不完整，未经测试):

class CStringIterator
{
public:
    CStringIterator(char *str=nullptr):
        ptr(str)
    {}

    bool operator==(const CStringIterator& other) const
    {
        if(other.ptr) {
            return ptr == other.ptr;
        } else {
            return !*ptr;
        }
    }

    /* ... operator++ and other iterator stuff */

private:
    char *ptr;
};

具体来说，我对转发迭代器感兴趣，因为我想避免进行迭代我知道算法只需要做一次就可以了.

解决方案

恐怕不是，最后，您将需要一个指向要调用strlen的字符串末尾的指针. /p>

Sometimes I need to pass a C string to a function using the common C++ iterator range interface [first, last). Is there a standard C++ iterator class for those cases, or a standard way of doing it without having to copy the string or call strlen()?

EDIT: I know I can use a pointer as an iterator, but I would have to know where the string ends, what would require me to call strlen().

EDIT2: While I didn't know if such iterator is standardized, I certainly know it is possible. Responding to the sarcastic answers and comments, this is the stub (incomplete, untested):

class CStringIterator
{
public:
    CStringIterator(char *str=nullptr):
        ptr(str)
    {}

    bool operator==(const CStringIterator& other) const
    {
        if(other.ptr) {
            return ptr == other.ptr;
        } else {
            return !*ptr;
        }
    }

    /* ... operator++ and other iterator stuff */

private:
    char *ptr;
};

EDIT3: Specifically, I am interested in a forward iterator, because I want to avoid to iterate over the sring twice, when I know the algorithm will only have to do it once.

解决方案

I'm afraid not, for last you'll need a pointer to the end of the string for which you'll need to call strlen.

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