c++ - 将先前分配的指针值传递给循环

Question

我有一个字符串指针string* ifxPtr;，我想做的是将这个指针设置为指向用户输入，然后循环遍历它的每个字符。

string* ifxPtr;

void Expression::GetInfix(string data) // This method runs first and it's setting the pointer to point to previously passed user input
{   
   ifxPtr = &data;
   ConvertToPostfix();
}

void Expression::ConvertToPostfix()
{
    for (int i = 0; i < *ifxPtr->length; i++) // Here's the struggle, compiler is complaining about *ifxPtr with message Cannot apply binary '<' to 'int' and 'unassigned() const'
    {
        //Do something here
    }
}

Answer 1

1. length 是一个函数，应该是 length()
2. 你如果您使用 ->
，则不需要引用指针
3. 结果从 length() 返回的是 size_t

这是我会用到的:

int length = static_cast<int>((*ifxPtr).length());