Pointer vs. Reference
My rule of thumb is: Use pointers if you want to do pointer arithmetic with them (e.g. incrementing the pointer address to step through an array) or if you ever have to pass a NULL-pointer. Use references otherwise.
pointers
What is the difference between char array and char pointer in C?
char* and char[] are different types, but it’s not immediately apparent in all cases. This is because arrays decay into pointers, meaning that if an expression of type char[] is provided where one of type char* is expected, the compiler automatically converts the array into a pointer to its first element. Your example function printSomething … Read more
Return array in a function
In this case, your array variable arr can actually also be treated as a pointer to the beginning of your array’s block in memory, by an implicit conversion. This syntax that you’re using: int fillarr(int arr[]) Is kind of just syntactic sugar. You could really replace it with this and it would still work: int … Read more
Pointer to class data member “::*”
It’s a “pointer to member” – the following code illustrates its use: #include <iostream> using namespace std; class Car { public: int speed; }; int main() { int Car::*pSpeed = &Car::speed; Car c1; c1.speed = 1; // direct access cout << “speed is ” << c1.speed << endl; c1.*pSpeed = 2; // access via pointer … Read more
NULL vs nullptr (Why was it replaced?) [duplicate]
nullptr has type std::nullptr_t. It’s implicitly convertible to any pointer type. Thus, it’ll match std::nullptr_t or pointer types in overload resolution, but not other types such as int. 0 (aka. C’s NULL bridged over into C++) could cause ambiguity in overloaded function resolution, among other things: f(int); f(foo *); (Thanks to Caleth pointing this out … Read more
Arrow operator (->) usage in C
foo->bar is equivalent to (*foo).bar, i.e. it gets the member called bar from the struct that foo points to.
Why does the arrow (->) operator in C exist?
I’ll interpret your question as two questions: 1) why -> even exists, and 2) why . does not automatically dereference the pointer. Answers to both questions have historical roots. Why does -> even exist? In one of the very first versions of C language (which I will refer as CRM for “C Reference Manual”, which … Read more
What is uintptr_t data type
First thing, at the time the question was asked, uintptr_t was not in C++. It’s in C99, in <stdint.h>, as an optional type. Many C++03 compilers do provide that file. It’s also in C++11, in <cstdint>, where again it is optional, and which refers to C99 for the definition. In C99, it is defined as … Read more
Differences between unique_ptr and shared_ptr [duplicate]
Both of these classes are smart pointers, which means that they automatically (in most cases) will deallocate the object that they point at when that object can no longer be referenced. The difference between the two is how many different pointers of each type can refer to a resource. When using unique_ptr, there can be … Read more
Why use double indirection? or Why use pointers to pointers?
If you want to have a list of characters (a word), you can use char *word If you want a list of words (a sentence), you can use char **sentence If you want a list of sentences (a monologue), you can use char ***monologue If you want a list of monologues (a biography), you can … Read more