C++ Const local variables


Example

Declaration and usage.

// a is const int, so it can't be changed
const int a = 15;  
a = 12;           // Error: can't assign new value to const variable
a += 1;           // Error: can't assign new value to const variable

Binding of references and pointers

int &b = a;       // Error: can't bind non-const reference to const variable
const int &c = a; // OK; c is a const reference

int *d = &a;      // Error: can't bind pointer-to-non-const to const variable
const int *e = &a // OK; e is a pointer-to-const

int f = 0;
e = &f;           // OK; e is a non-const pointer-to-const,
                  // which means that it can be rebound to new int* or const int*

*e = 1            // Error: e is a pointer-to-const which means that
                  // the value it points to can't be changed through dereferencing e

int *g = &f;
*g = 1;           // OK; this value still can be changed through dereferencing
                  // a pointer-not-to-const