Скачать или смотреть 3/N - (Fundamentals) A Pointer, a Reference, a const in C/C++

We will learn C/C++ pointer arithmetic.

int n = 5;

int* ptr = &n;

What does int* mean to C++ compiler?

It has 3 implications:

(1) int* instructs C++ compiler... when the pointer ptr is dereferenced with *

*ptr,

this int* instructs the C++ compiler to retrieve sizeof(int) bytes from the start of
int n's address, and return the value at that address.

(2) int* instructs C++ compiler to regard pointer arithmetic with 4-bytes unit.

Since ptr is of type int*, ptr + 1 = the address of n + sizeof(int) bytes

ptr + 1 = the next (or the integer residing 4 bytes higher)

(3) int* instructs C++ compiler to implicitly define array indexing operator [].

ptr[0] = the value at the address of n
ptr[1] = the value at (the address of n + 4-bytes), sizeof(int) = 4 bytes.
ptr[2] = the value at (the address of n + 8-bytes)

1/N - a Pointer, a Reference, a const in C/C++
   • 1/N - a Pointer, a Reference, a const in C...  

int n = 5;
int* ptr = &n; // ptr is a pointer that points to a int n.
// ptr or pointer is an object.

int& r = n; // r is a reference, and r is an alias not an object.

const int& cr = n; // const lvalue reference initialized with an object is an alias, not an object.

const int& ccr = 5; // const lvalue reference initialized
// with a literal value is an object, not an alias

2/N - a Pointer, a Reference, a const in C++
   • 2/N - a Pointer, a Reference, a const in C++  

int n = 5;
int* ptr = &n; // the star * is a declarator if it follows a type, such as int, double.
// in this case, since type int precedes the star *
// this star * is a pointer declarator

int& r = n; // the ampersand & follows a type int, so
// the ampersand & is a reference declarator.

If the star * does not follow a type but precedes an expression, then
the star * (or asterisk) is a dereference operator.

If the ampersand does not follow a type but precedes an expression, then the ampersand & is an address-of operator.

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