References, Pointers and Constants

Simple C++ Data Types

const char *
const int *
const double * char * &
int * &
double * & char * const
int * const
double * const

C++ Code	What It Means	When To Use It
char int double	Single (scalar) value (character, integer, floating point number)	To store data To pass data to a function by value To return data by value
const char const int const double	Constant value	To declare a constant -- a value that cannot be changed Has no effect for passing values to a function or from returning values from a function
char [] int [] double []	Array (vector) of values (char [] is a string)	To store the same type of data together To pass an array to a function
const char [] const int [] const double []	Constant array of values (const char [] is a string constant)	To declare an array of constant values (no element in the array can be changed) const char [] is used to declare a string constant
char * int * double *	Pointer to a single value or an array of values	To store a string (char *) To store an array of values when you have to allocate the memory dynamically (using new) To pass an array to a function To pass a value to a function which the function will set (passing by reference) To return a dynamically-allocated array from a function.
Pointer to a constant value	When you don't want the value at the pointer to be changed, but you can still change the pointer To return a pointer to a constant value To pass a pointer to a constant value to a function
char & int & double &	Reference to a value	To pass a value to a function which will be set by the function (without using a pointer)
Reference to a pointer	To pass a pointer to a function where the function will set the pointer (either by calling new or by assigning to the pointer
Constant pointer	When you want to point to a specific value. Allows to you to change the data that is pointed to, but you can't change the pointer