What is the <=> ("spaceship", three-way comparison) operator in …
Nov 24, 2017 · This is called the three-way comparison operator. According to the P0515 paper proposal: There’s a new three-way comparison operator, <=>. The expression a <=> b returns …
How to use the PI constant in C++ - Stack Overflow
Nov 13, 2009 · I want to use the PI constant and trigonometric functions in some C++ program. I get the trigonometric functions with include <math.h>. However, there doesn't seem to be …
What is the purpose of using #ifdef and #if in C++?
The meaning of #ifdef is that the code inside the block will be included in the compilation only if the mentioned preprocessor macro is defined. Similarly, #if means that the block will be …
Regular cast vs. static_cast vs. dynamic_cast - Stack Overflow
Aug 26, 2008 · I've been writing C and C++ code for almost twenty years, but there's one aspect of these languages that I've never really understood. I've obviously used regular casts i.e. …
Proper way to initialize C++ structs - Stack Overflow
Jan 21, 2017 · Our code involves a POD (Plain Old Datastructure) struct (it is a basic c++ struct that has other structs and POD variables in it that needs to get initialized in the beginning.) …
c++ - How can I convert a std::string to int? - Stack Overflow
Nov 20, 2014 · I want to convert a string to an int and I don't mean ASCII codes. For a quick run-down, we are passed in an equation as a string. We are to break it down, format it correctly …
How do I fix the error "was not declared in this scope"?
This is similar to how one would write a prototype for functions in a header file and then define the functions in a .cpp file. A function prototype is a function without a body and lets the compiler …
What does the C++ standard say about the size of int, long?
I'm looking for detailed information regarding the size of basic C++ types. I know that it depends on the architecture (16 bits, 32 bits, 64 bits) and the compiler. But are there any standards for ...
How to call a parent class function from derived class function?
How do I call the parent function from a derived class using C++? For example, I have a class called parent, and a class called child which is derived from parent. Within each class there is …
What's the difference between constexpr and const?
What's the difference between constexpr and const? When can I use only one of them? When can I use both and how should I choose one?