What is the difference between const int*, const int * const, and int . . . const int *p;: When p is dereferenced with *, the expression is of type const int Therefore, p is a pointer to const int int *const p;: p is const If this constant expression is dereferenced with *, the expression is of type int Therefore, p is a const pointer to int const int *const p;: p is const
constants - What does const mean in C++? - Stack Overflow int const* is a [non-const] pointer to a const int int const* const is a const pointer to a const int For whatever unfortunate accident in history, however, it was found reasonable to also allow the top-level const to be written on the left, i e , const int and int const are absolutely equivalent
What is the difference between const and const {} in JavaScript? const email = obj email; const title = obj title; This is old school now We can use ES6 destructuring assignment, i e , if our object contains 20 fields in the obj object, then we just have to write names of those fields which we want to use like this:
What is a const member function? - Stack Overflow The method bar() is non-const and can only be accessed from non-const values void func1(const foobar fb1, foobar fb2) { const char* v1 = fb1 bar(); won't compile const char* v2 = fb2 bar(); works } The idea behind const though is to mark methods which will not alter the internal state of the class This is a powerful concept but is not
class - Why put const (. . . ) in C++ - Stack Overflow const is only useful to enforce correctness, ie tell the compiler that if the developer directly modifies the object through the const reference, he is to be told off – spectras Commented Jun 28, 2017 at 7:03
How do I best use the const keyword in C? - Stack Overflow volatile still overrides const and register but const register combines both optimisations on C++ Even though all the above code is compiled using the default implicit -O0, when compiled with -Ofast, const surprisingly still isn't redundant on C or C++ on clang or gcc for file-scoped consts
Why can we use `std::move` on a `const` object? - Stack Overflow The reason we have const keyword in the language is that we want the compiler to prevent any change to an object defined to be const Given the example in Scott Meyers' book: class Annotation { public: explicit Annotation(const std::string text) : value(std::move(text)) "move" text into value; this code { … } doesn't do what it seems to!
c - Constant pointer vs Pointer to constant - Stack Overflow int a = 10; int *const ptr = a; *ptr = 5; right ptr++; wrong Generally I would prefer the declaration like this which make it easy to read and understand (read from right to left): int const *ptr; ptr is a pointer to constant int int *const ptr; ptr is a constant pointer to int