Question

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what is the difference between const int*, const int * const, int const *

i have a cpp code wich i’m having trouble reading. a class B is defined
now, i understand the first two lines, but the rest isn’t clear enough.
is the line “B const * pa2 = pa1” defines a const variable of type class B?
if so, what does the next line do?

B a2(2);
B *pa1 = new B(a2);
B const * pa2 = pa1;
B const * const pa3 = pa2;

also, i’m having trouble figuring out the difference between these two:

char const *cst = “abc”;
const int ci = 15;

thank you

Answer 1

This code declares a pointer to a constant B – in other words, it cannot be used to change the value of what it is pointing to:

B const * pa2 = pa1;

Alternatively, the following code declares a constant pointer to a constant B – so, pa3 cannot be used to change the value of what it is pointing to, and it cannot be modified to point to something else:

B const * const pa3 = pa2;

This page contains an explanation of const pointers.

To address your second question,

char const *cst = “abc”; – Declares a pointer to a constant char – in this case it is the string “abc”.

const int ci = 15; – Declares a constant integer 15, which cannot be changed.