Question

Please have a look at the following code

#include <iostream>

using namespace std;

int main()
{
    int a = 5;

    int *aPtr1 = &a;
    int *aPtr2 = aPtr1;
    int *aPtr3 = aPtr2;

    cout << "'a' value: " << a << endl;
    cout << "'aPtr1' value: " << *aPtr1 << endl;
    cout << "'aPtr2' value: " << *aPtr2 << endl;
    cout << "'aPtr2' value from 'aPtr3': " << **aPtr3 << endl;
}

In here, at the last line, I am trying to get the ‘aPtr2’ value from ‘aPtr3’. In other words, this is my attempt to find the ‘Pointer Before’. But it gives me the error

PointerTest.cpp:16: error: invalid type argument of `unary *'

How can I make this OK? Please help!

Answer 1

aPtr3 is equal to aPtr2. And aPtr2 is the adress of a. When writing *aPtr3, you already access the value pointed by the adress it contains (ie, the adress of a).

If you wanted to use this syntax, you should have had

int **aPtr3 = &aPtr2;