The C++ Data Types

Constant Pointers, Pointers to Constants, and References to Constants

A constant pointer: int I, int *const cp = &I;

// cp is initialized to point to I

// cp can not point to any other object

A pointer to a constant: const int ci = 10; const int* pc = &ci;

// pc is variable pointer to a constant integer

*pc = 15 // this gives an error, ci is a constant integer

reference to a constant: const float pi = 3.1.1;

const float& unit_circle_area = pi;

A constant reference can also be defined for a variable data object

double x; const double& xr = x; // xr can be a function argument

// xr refers to x as a const data object of type double

xr = 10.0; // gives error, where x = 10.0; x *= 100.0; // are OK

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