如何理解 c++ 中这样的代码 [request->headers().Method()->value().getStringView())]

Question

I am suppose to reduce it down to [request->headers().getMethodValue())] .

I am fairly new to C++. Can someone please tell me how to understand this type of code? There are multiple . operator and -> operator. I loose track of the classes and others.

It's a little overwhelming.

Answer 1

Actually, those type of codes are common in languages that supports object-oriented programming.

The most likely reason is that if combined well with class hierarchy and inheritance, the single line reduces many if-else statement to terse syntax like one you mentioned. I suggest you study about object-oriented programming styles, especially polymorphism to understand this kind of code.

Answer 2

The . operator is used to access stuff inside the object (functions, variables etc.) the -> operator is just a . operator but for pointers. In your case you call request 's headers function that returns an object. For that object then you call getMethodValue function.

Answer 3

Answers already explained, what for . operator and -> operator;

an example would be;

class Test
{
    public:
      print( int i) { std::cout << i << std::endl; }
};

to access pointer object

Test* tPtr;

tPtr->print() // prints i;

to access object;

Test tObj;

tObj.print() // print i;